Pariksha SaathiPedagogy
CTET Science MCQ with Answers, Paper 2
353 practice questions on Science and its Pedagogy (Paper II) for CTET Paper II (Mathematics and Science), with answers; most also have an explanation or a worked solution. Try each one before you open its answer.
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Q.251
Which of the following is NOT a root that we eat?
- A Carrot
- B Potato
- C Radish
- D Sweet potato
Show answer
Correct answer: (B) Potato
Potato is an underground stem; its 'eyes' are buds from which new shoots grow. Carrot, radish and sweet potato are roots that store food.
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Q.252
Developing scientific temper, humanism and the spirit of inquiry and reform is a Fundamental Duty of every Indian citizen under which clause of Article 51A of the Constitution?
- A Article 51A(a)
- B Article 51A(g)
- C Article 51A(h)
- D Article 51A(k)
Show answer
Correct answer: (C) Article 51A(h)
Article 51A(h) requires citizens to develop scientific temper, humanism and the spirit of inquiry and reform. 51A(g) concerns the natural environment and 51A(k) the duty of parents to provide education to children aged six to fourteen.
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Q.253
Which of the following is an example of a fixed joint, at which the bones cannot move?
- A The joint where the neck joins the head
- B The joint between the upper jaw and the rest of the head
- C The joint between the thigh bone and the lower leg at the knee
- D The joint between the thigh bone and the hip
Show answer
Correct answer: (B) The joint between the upper jaw and the rest of the head
The bones of the upper jaw are joined to the rest of the head by fixed joints, so they cannot move; only the lower jaw moves when we chew. The neck-head joint is a pivotal joint, the knee a hinge joint and the hip a ball and socket joint.
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Q.254
A tough, porous, black product of coal that is an almost pure form of carbon and is used in the manufacture of steel is:
- A Coke
- B Coal tar
- C Coal gas
- D Bitumen
Show answer
Correct answer: (A) Coke
Coke is almost pure carbon and is used in making steel and in extracting many metals. Coal tar is a thick black liquid used to make dyes, drugs and naphthalene balls, and coal gas is used as a fuel.
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Q.255
Which pair of a hormone and the gland that secretes it is NOT correctly matched?
- A Testosterone – testes
- B Insulin – adrenal gland
- C Oestrogen – ovaries
- D Thyroxine – thyroid gland
Show answer
Correct answer: (B) Insulin – adrenal gland
Insulin is secreted by the pancreas; the adrenal glands secrete adrenalin. Testosterone comes from the testes, oestrogen from the ovaries and thyroxine from the thyroid gland.
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Q.256
How do forests help to prevent floods in nearby areas?
- A Forest soil and plants soak up rain and let it seep in slowly
- B Trees prevent clouds from forming over the forest area
- C Tall trees send rainwater quickly down into the rivers
- D Forest animals drink most of the rainwater that falls in the forest
Show answer
Correct answer: (A) Forest soil and plants soak up rain and let it seep in slowly
Forests act as natural absorbers of rainwater: the roots, the layer of dead leaves and the porous soil hold the water and let it seep into the ground. This reduces sudden run-off, helps prevent floods and helps maintain the water table.
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Q.257
A committee proposes teaching the quantum-mechanical model of the atom, with its equations, to Class 6 students. According to the NCF 2005 validity criteria for a science curriculum, this mainly violates:
- A Historical validity
- B Cognitive validity
- C Environmental validity
- D Ethical validity
Show answer
Correct answer: (B) Cognitive validity
Cognitive validity requires that the content, process, language and teaching practices of the curriculum be age-appropriate and within the cognitive reach of the child. A highly abstract mathematical model of the atom is far beyond Class 6 learners.
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Q.258
A group of students wants to test the effect of the amount of sunlight on the growth of bean plants. In this experiment the INDEPENDENT variable is:
- A Height of the plants
- B Amount of sunlight
- C Amount of water given
- D Type of soil used
Show answer
Correct answer: (B) Amount of sunlight
The independent variable is the one the experimenter deliberately changes (sunlight). Plant height is the dependent variable that is measured, while water and soil must be kept the same as controlled variables.
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Q.259
In Krathwohl's taxonomy of the affective domain, which of the following is the highest level?
- A Receiving
- B Valuing
- C Organisation
- D Characterisation by a value or value complex
Show answer
Correct answer: (D) Characterisation by a value or value complex
The affective domain rises from receiving, responding and valuing to organisation and finally characterisation, where a consistent value system guides behaviour, as in a learner who habitually acts with scientific honesty.
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Q.260
Match the animal (List I) with the organ through which it mainly breathes (List II):
A. Cockroach
B. Earthworm
C. Fish
D. Adult frog
1. Gills
2. Spiracles and tracheae
3. Moist skin only
4. Lungs, and also the skin
- A A-3, B-2, C-1, D-4
- B A-2, B-3, C-4, D-1
- C A-1, B-3, C-2, D-4
- D A-2, B-3, C-1, D-4
Show answer
Correct answer: (D) A-2, B-3, C-1, D-4
A cockroach takes in air through spiracles that lead into a network of tracheae; an earthworm breathes through its moist skin; a fish uses gills to take in oxygen dissolved in water; a frog has lungs and can also breathe through its moist skin.
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Q.261
A Class 7 student says, 'Plants get their food from the soil through their roots.' From a science teacher's point of view this is:
- A Fully correct
- B Partially correct, since roots absorb ready-made food from the soil
- C Correct only for crop plants
- D A misconception; plants make their own food by photosynthesis, while soil supplies water and minerals
Show answer
Correct answer: (D) A misconception; plants make their own food by photosynthesis, while soil supplies water and minerals
Plants are autotrophs that synthesise food from carbon dioxide and water using light. The soil provides water and mineral nutrients, not food, so the belief must be addressed through activities on photosynthesis.
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Q.262
Rekha connects a bulb to a fresh cell correctly, but the bulb does not glow. When she puts another bulb in the same circuit, the new bulb glows. The most likely reason is that the first bulb:
- A Will glow only with a battery of several cells
- B Is fused, that is, its filament is broken
- C Has a filament made of an insulating material
- D Was not kept in the circuit long enough to light
Show answer
Correct answer: (B) Is fused, that is, its filament is broken
Since the cell and the circuit work with another bulb, the fault is in the first bulb. A bulb whose filament is broken is said to be fused; the circuit through it is incomplete, so no current flows.
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Q.263
While the switch of an electric bell is kept pressed, its hammer strikes the gong again and again. Why does this happen?
- A The gong is itself a magnet that repels the hammer each time it is struck
- B The cell switches the current on and off by itself at regular intervals
- C Sound waves from the gong push the hammer back so that it can strike again
- D Pulling the strip breaks the circuit; the strip springs back and remakes it
Show answer
Correct answer: (D) Pulling the strip breaks the circuit; the strip springs back and remakes it
Current makes the coil an electromagnet, which pulls the iron strip so that the hammer strikes the gong; this moves the strip away from the contact screw and breaks the circuit. The electromagnet stops being a magnet, the strip springs back, the circuit is completed, and the cycle repeats.
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Q.264
Sponges and Hydra have no circulatory system. How do their cells get food and oxygen?
- A They have a simple heart that pumps a colourless fluid through the body
- B Their cells make all the food and oxygen they need by photosynthesis
- C Water entering their bodies brings in food and oxygen
- D They keep enough food and oxygen stored in one large vacuole
Show answer
Correct answer: (C) Water entering their bodies brings in food and oxygen
Animals such as sponges and Hydra do not have a circulatory system. The water in which they live brings food and oxygen as it enters their bodies, and carries away waste as it moves out.
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Q.265
According to NCF 2005, a science curriculum should place scientific ideas in the developmental context of how they evolved over time, so that students see science as a human, social enterprise. This criterion is:
- A Cognitive validity
- B Environmental validity
- C Process validity
- D Historical validity
Show answer
Correct answer: (D) Historical validity
Historical validity means science is taught in its historical and developmental context, showing how concepts evolved. Environmental validity relates science to the local and global environment, and process validity to engaging with the methods of science.
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Q.266
A bee carries pollen from a flower on one mustard plant to the stigma of a flower on a different mustard plant. This is an example of:
- A Cross-pollination
- B Self-pollination
- C Fertilisation
- D Seed dispersal
Show answer
Correct answer: (A) Cross-pollination
Transfer of pollen to the stigma of a flower on a different plant of the same kind is cross-pollination; transfer within the same flower or to another flower of the same plant is self-pollination. Fertilisation happens later, when the male and female gametes fuse.
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Q.267
A simple pendulum completes 20 oscillations in 32 seconds. What is its time period?
- A 1.6 s
- B 0.625 s
- C 3.2 s
- D 12 s
Show answer
Correct answer: (A) 1.6 s
Time period = total time / number of oscillations = 32 s / 20 = 1.6 s. Dividing 20 by 32 (0.625) turns the ratio upside down and gives the number of oscillations per second, not the time period.
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Q.268
In the 5E instructional model, the phase that comes immediately after 'Engage' is:
- A Explore
- B Explain
- C Elaborate
- D Evaluate
Show answer
Correct answer: (A) Explore
The 5E sequence is Engage, Explore, Explain, Elaborate and Evaluate. After capturing interest in the Engage phase, students explore the concept through hands-on activity before the teacher explains it formally.
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Q.269
A teacher asks students what will happen when an 'empty' glass is pushed upside down into a bucket of water, lets them watch it happen, and then asks them to explain any difference between what they expected and what they saw. This strategy is:
- A Jigsaw
- B Brainstorming
- C Predict-Observe-Explain (POE)
- D Think-Pair-Share cooperative strategy
Show answer
Correct answer: (C) Predict-Observe-Explain (POE)
In Predict-Observe-Explain, students first predict and give reasons, then observe, and finally reconcile the two. It brings out their ideas and creates useful cognitive conflict when the observation surprises them.
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Q.270
The heuristic method of teaching science, in which the pupil is placed in the position of a discoverer, is associated with:
- A John Dewey
- B H.E. Armstrong
- C W.H. Kilpatrick
- D Maria Montessori
Show answer
Correct answer: (B) H.E. Armstrong
H.E. Armstrong advocated the heuristic method ('heurisko' means 'I find'), in which students find out things for themselves. Kilpatrick is linked to the project method and Dewey to problem-solving and reflective thinking.
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Q.271
Consider the following statements:
1. Scientists can now predict exactly when and where an earthquake will strike.
2. A strong earthquake under the ocean floor can cause a tsunami.
Which of the statements given above is/are correct?
- A Only 1
- B Only 2
- C Both 1 and 2
- D Neither 1 nor 2
Show answer
Correct answer: (B) Only 2
Statement 1 is wrong: so far no one can predict when and where an earthquake will occur, which is why precautions are important. Statement 2 is right: a strong earthquake under the sea can set off the huge ocean waves of a tsunami.
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Q.272
Which of the following is NOT a way of reducing friction?
- A Making treads (grooves) on the tyres of vehicles
- B Applying oil or grease to the moving parts of a machine
- C Using ball bearings between the hub and the axle of a cycle wheel
- D Sprinkling fine powder on a carrom board
Show answer
Correct answer: (A) Making treads (grooves) on the tyres of vehicles
Treads on tyres give a better grip on the road and so increase friction. Lubricants, ball bearings and fine powder all reduce friction.
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Q.273
After stirring sugar into water, a student says, 'The sugar has disappeared; it no longer exists.' Which observation can the teacher use to challenge this idea?
- A The solution looks clear and transparent, just like plain water from the tap
- B The spoon used for stirring has become wet
- C The sugar particles can no longer be seen in the glass
- D The water tastes sweet, and the total mass is unchanged after mixing
Show answer
Correct answer: (D) The water tastes sweet, and the total mass is unchanged after mixing
The sweet taste and unchanged total mass show that the sugar is still present, its particles having spread out among the water particles. Noting only that the sugar cannot be seen supports, rather than challenges, the child's idea.
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Q.274
The main purpose of a diagnostic test in science is to:
- A Rank students of the class in order of merit
- B Decide which students will be promoted to the next class
- C Issue a certificate of achievement
- D Identify specific learning difficulties so that remedial teaching can be planned
Show answer
Correct answer: (D) Identify specific learning difficulties so that remedial teaching can be planned
A diagnostic test pinpoints exactly where and why a learner is going wrong; it is followed by remedial teaching. Ranking and promotion are purposes of summative assessment.
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Q.275
On the same distance-time graph, the lines for two cars P and Q are both straight, but the line for P is steeper. What can be concluded?
- A Both move with uniform speed, and Q is faster than P
- B The speed of P is increasing while that of Q is constant
- C Both cars are at rest, since their lines are straight
- D Both move with uniform speed, and P is faster than Q
Show answer
Correct answer: (D) Both move with uniform speed, and P is faster than Q
A straight-line distance-time graph shows uniform speed. The steeper line means more distance is covered in the same time, so P is faster.
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Q.276
Match the petroleum product in List I with its use in List II.
List I: A. Bitumen B. Paraffin wax C. Diesel D. Kerosene
List II: 1. Fuel for stoves, lamps and jet aircraft 2. Paints and road surfacing 3. Ointments, candles and vaseline 4. Fuel for heavy motor vehicles and electric generators
- A A-2, B-3, C-4, D-1
- B A-3, B-2, C-1, D-4
- C A-2, B-4, C-3, D-1
- D A-1, B-3, C-4, D-2
Show answer
Correct answer: (A) A-2, B-3, C-4, D-1
Bitumen is used in paints and road surfacing, paraffin wax in ointments, candles and vaseline, diesel in heavy vehicles and generators, and kerosene in stoves, lamps and jet aircraft. All of them are separated from petroleum in a refinery.
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Q.277
When an electric current is passed through a conducting solution, which of the following is NOT one of the chemical effects that may be observed?
- A Bubbles of gas form on the electrodes
- B The solution itself starts to glow with light
- C A layer of metal is deposited on an electrode
- D The colour of the solution changes
Show answer
Correct answer: (B) The solution itself starts to glow with light
Gas bubbles at the electrodes, deposits of metal on them and changes in the colour of the solution are chemical effects of electric current. The solution itself does not give out light.
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Q.278
A Class 6 student predicts that the shadow of a red ball will be red and the shadow of a green leaf will be green. This prediction is:
- A Correct, because the shadow of an object always takes on the colour of that object
- B A misconception; an opaque object's shadow is dark whatever its colour
- C Correct only when the object is placed in bright sunlight
- D Correct only when the object is held very close to the screen
Show answer
Correct answer: (B) A misconception; an opaque object's shadow is dark whatever its colour
A shadow forms where an opaque object blocks light, so it is dark irrespective of the object's colour. Letting children make shadows of differently coloured objects on a screen lets them test the prediction themselves.
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Q.279
A female frog lays hundreds of eggs at a time, while a hen usually lays one egg at a time. The best explanation for the frog laying so many eggs is that:
- A Frog eggs are fertilised inside the body, so a larger number has to be produced
- B In external fertilisation, many eggs are lost or never fertilised
- C A frog egg can develop into an adult only if it is laid along with many others
- D Frogs are viviparous and have to give birth to many young ones at a time
Show answer
Correct answer: (B) In external fertilisation, many eggs are lost or never fertilised
In frogs fertilisation is external: eggs and sperms meet in water, where many are washed away by water movement, wind or rain, or eaten by other animals. Laying a large number of eggs raises the chance that some are fertilised and survive; a hen has internal fertilisation.
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Q.280
An object goes round and round a fixed point so that its distance from that point always remains the same, like the tip of a clock's hand. This type of motion is called:
- A Rectilinear motion
- B Circular motion
- C Oscillatory motion
- D Random motion
Show answer
Correct answer: (B) Circular motion
In circular motion the object moves along a circle, so its distance from the centre stays the same, as with the tip of a clock's hand or a point on a fan blade. In rectilinear motion the object moves along a straight line.
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Q.281
In a wastewater treatment plant, large objects such as rags, sticks, cans and plastic packets are removed at the first stage by passing the wastewater through:
- A A grit and sand removal tank
- B An aeration tank
- C A large settling tank (clarifier)
- D Bar screens
Show answer
Correct answer: (D) Bar screens
Wastewater first passes through bar screens, which remove large objects. It then goes to a grit and sand removal tank, next to a large settling tank where solids such as faeces settle as sludge, and later the clarified water is aerated.
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Q.282
An electric bell ringing inside a glass jar can be heard clearly. As the air is gradually pumped out of the jar, the sound becomes fainter and fainter. This shows that:
- A Glass does not allow any sound to pass through it
- B The bell vibrates less once the air is removed
- C Sound needs a medium such as air to travel
- D Sound travels faster when there is less air
Show answer
Correct answer: (C) Sound needs a medium such as air to travel
The bell keeps vibrating, but with less air there is less medium to carry the sound to us. Sound cannot travel through a vacuum; it travels through solids, liquids and gases.
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Q.283
During a storm, the tin roofs of some houses are lifted and blown away. The best explanation is that:
- A Fast wind above the roof raises the pressure there, which pulls the roof up into the air
- B Rain falling on the roof makes it lighter, so that even a gentle wind can lift it
- C Fast wind above the roof lowers the pressure there, so air pressure from below pushes it up
- D Thunder during the storm shakes the roof until all its nails come loose
Show answer
Correct answer: (C) Fast wind above the roof lowers the pressure there, so air pressure from below pushes it up
Increased wind speed is accompanied by reduced air pressure. The fast wind over the roof lowers the pressure above it, while the greater pressure of the air below pushes the roof up.
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Q.284
Why is it useful for a plant that its seeds are dispersed away from the parent plant?
- A Seeds can germinate only after they have travelled a long distance
- B Seedlings avoid competing with the parent for light and water
- C Dispersal is needed before pollination can take place in the flower
- D Seeds can be fertilised only after they have left the parent plant
Show answer
Correct answer: (B) Seedlings avoid competing with the parent for light and water
If all the seeds fell under the parent plant, the seedlings would compete with it for sunlight, water and minerals. Dispersal avoids this and also helps the plant to reach new habitats.
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Q.285
A teacher makes a simple lens from a drop of water, a pinhole camera from a shoebox and a balance from a hanger. The chief advantage of such low-cost, no-cost improvised apparatus is that it:
- A Makes science concrete, accessible and inexpensive while encouraging creativity
- B Completely replaces the need for any laboratory equipment
- C Gives greater accuracy than standard laboratory apparatus
- D Reduces the teacher's preparation work to zero
Show answer
Correct answer: (A) Makes science concrete, accessible and inexpensive while encouraging creativity
Improvised apparatus from everyday materials lets every child do science even without a formal lab and fosters creativity and resourcefulness; it complements rather than replaces standard apparatus and is not more accurate.
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Q.286
Which of the following objectives of science teaching belongs to the AFFECTIVE domain?
- A The student focuses a hand lens correctly and steadily to observe the stamens and pistil of a flower
- B The student draws a neat, labelled diagram of a flower
- C The student records observations honestly even when they differ from what was expected
- D The student names the parts of a flower
Show answer
Correct answer: (C) The student records observations honestly even when they differ from what was expected
The affective domain deals with attitudes, values and interests, such as honesty in reporting observations. Focusing a lens and drawing are psychomotor skills, and naming parts is cognitive recall.
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Q.287
On the Richter scale, how does the destructive energy of an earthquake of magnitude 6 compare with that of one of magnitude 4?
- A It is one and a half times more
- B It is exactly twice as much
- C It is about ten times more
- D It is about a thousand times more
Show answer
Correct answer: (D) It is about a thousand times more
The Richter scale is not linear: a rise of 2 in magnitude means about a thousand times more destructive energy. So a magnitude 6 earthquake is not just 1.5 times as destructive as one of magnitude 4.
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Q.288
In group projects a teacher finds that one or two students do all the work while the others do little. Which step best addresses this, in line with cooperative learning?
- A Award one common grade to the whole group for the final product only
- B Let the most capable student in each group complete the whole project on everyone's behalf
- C Give each member a specific role and also assess each member's own contribution
- D Stop group work altogether and give only individual tasks
Show answer
Correct answer: (C) Give each member a specific role and also assess each member's own contribution
Cooperative learning needs both positive interdependence and individual accountability. Clear roles and assessment of each learner's contribution prevent 'free riding', which a single shared grade can encourage.
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Q.289
A lens that is thicker in the middle than at the edges:
- A Is a concave lens and converges the light falling on it
- B Is a convex lens and spreads out the light falling on it
- C Is a concave lens and spreads out the light falling on it
- D Is a convex lens and converges the light falling on it
Show answer
Correct answer: (D) Is a convex lens and converges the light falling on it
A convex lens is thicker in the middle and bends parallel rays towards each other, that is, it converges them; this is why it can concentrate sunlight into a bright spot. A concave lens is thinner in the middle and spreads light out.
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Q.290
In the 'Jigsaw' technique of cooperative learning:
- A The teacher lectures while groups take notes together
- B Each member of a group becomes an 'expert' on one part of the topic and teaches it to the others
- C Students compete individually to finish a puzzle fastest
- D Only the brightest student of each group presents the work
Show answer
Correct answer: (B) Each member of a group becomes an 'expert' on one part of the topic and teaches it to the others
In Jigsaw, a topic is divided into parts; members from different groups who share the same part meet as 'expert groups' and then return to teach their home group, so every learner is both teacher and learner.
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Q.291
A tester made with a torch bulb is dipped in lemon juice and the bulb does not glow. A student concludes that lemon juice does not conduct electricity. Why may this conclusion be wrong?
- A The current may be too weak to light the bulb, though an LED could show it
- B Lemon juice conducts electricity only after it has been heated to boiling
- C A bulb in a tester can never glow when the liquid being tested is an acid
- D Lemon juice is a good conductor only when the tester is kept in sunlight
Show answer
Correct answer: (A) The current may be too weak to light the bulb, though an LED could show it
A weak current may not heat the bulb's filament enough to make it glow even though the liquid conducts. An LED glows with a much weaker current, and the deflection of a compass needle (magnetic effect) also shows a small current.
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Q.292
Which of the following is NOT a consequence of large-scale deforestation?
- A A rise in the level of groundwater
- B Greater erosion of the soil
- C More frequent floods and droughts
- D More carbon dioxide in the atmosphere
Show answer
Correct answer: (A) A rise in the level of groundwater
Deforestation lowers the groundwater level, because less rainwater seeps into the ground when there are no trees and forest floor to hold it. It also increases soil erosion, floods, droughts and the carbon dioxide in the air, and can lead to desertification.
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Q.293
Which statement best captures the 'tentative' nature of scientific knowledge?
- A Scientific facts, once proved, can never be changed
- B Scientific knowledge is open to revision in the light of new evidence
- C Scientific knowledge depends on the opinion of famous scientists
- D Scientific laws hold true only inside laboratories
Show answer
Correct answer: (B) Scientific knowledge is open to revision in the light of new evidence
Science is tentative because every conclusion remains open to modification when new evidence or better explanations appear. It is not fixed for ever, nor is it a matter of authority or opinion.
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Q.294
A special whistle produces a sound of frequency about 25,000 Hz. Which statement about this sound is correct?
- A Both a human and a dog can hear it
- B A human cannot hear it, but a dog can
- C A human can hear it, but a dog cannot
- D Neither a human nor a dog can hear it
Show answer
Correct answer: (B) A human cannot hear it, but a dog can
The human ear can hear sounds from about 20 Hz to 20,000 Hz, so 25,000 Hz is inaudible to us. Some animals, such as dogs, can hear sounds of frequencies higher than 20,000 Hz.
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Q.295
It is safer to wear cotton clothes rather than synthetic clothes while cooking or working in a laboratory, because synthetic fibres:
- A Absorb too much water and become very heavy
- B Conduct electricity and can give electric shocks
- C Melt on heating and stick to the body if they catch fire
- D Are weak and tear easily when near a flame
Show answer
Correct answer: (C) Melt on heating and stick to the body if they catch fire
Synthetic fibres melt on heating; if such clothes catch fire, the molten material sticks to the body and causes severe burns. Cotton does not melt in this way.
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Q.296
Cranes in scrap yards use an electromagnet, rather than a permanent magnet, to lift heavy pieces of iron. The main advantage is that the electromagnet:
- A Attracts scrap made of copper and aluminium as well as scrap made of iron
- B Keeps its magnetism permanently, even when no current flows through it
- C Works without needing any electric current to be passed through its coil
- D Loses its magnetism when the current is switched off, releasing the load
Show answer
Correct answer: (D) Loses its magnetism when the current is switched off, releasing the load
An electromagnet is a magnet only while current flows through its coil. Switching the current off releases the iron load at the desired place, which a permanent magnet cannot do.
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Q.297
A clinical thermometer has a kink near its bulb. The purpose of the kink is to:
- A Let the mercury rise faster up into the narrow glass tube
- B Make the thermometer stronger so that it does not break easily
- C Allow the thermometer to measure temperatures above 42 °C
- D Stop the mercury from falling back on its own after it is taken out
Show answer
Correct answer: (D) Stop the mercury from falling back on its own after it is taken out
The kink prevents the mercury from slipping back into the bulb on its own, so the reading can be taken after the thermometer is removed from the mouth. That is why the thermometer is given a few jerks before use.
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Q.298
Which pair consists only of non-contact forces?
- A Muscular force and magnetic force
- B Gravitational force and electrostatic force
- C Frictional force and gravitational force
- D Electrostatic force and frictional force
Show answer
Correct answer: (B) Gravitational force and electrostatic force
Magnetic, electrostatic and gravitational forces act even without contact, so they are non-contact forces. Muscular force and friction act only when the objects are in contact.
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Q.299
A nerve cell is long and has many branches. How does this shape suit its function?
- A It can squeeze through narrow blood vessels to carry oxygen
- B It can receive and pass on messages across the body
- C It can change its shape to surround and destroy germs
- D It can store large amounts of food for the rest of the body
Show answer
Correct answer: (B) It can receive and pass on messages across the body
The nerve cell receives and transfers messages, which helps to control and coordinate the working of different parts of the body; its long, branched shape suits this. Carrying oxygen is the work of red blood cells, and destroying germs is done by white blood cells.
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Q.300
Which of the following is NOT an adaptation of the camel to life in the desert?
- A A thick layer of fat under the skin that keeps the body warm
- B Long legs that keep its body away from the hot sand
- C Passing only a little urine and producing very dry dung
- D Sweating very little, so that hardly any water is lost
Show answer
Correct answer: (A) A thick layer of fat under the skin that keeps the body warm
Long legs, little urine, dry dung and very little sweating help a camel survive heat and shortage of water. A thick layer of fat under the skin for warmth is an adaptation of animals of cold regions, such as the polar bear.
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How these questions were made
Authored by an AI assistant (Claude) from its own general knowledge of stable, well-established facts (no live lookup) - not reviewed by a subject-matter expert; verify against an official source before relying on any fact.