"Science — Food" — Practice

Question 1

Which of the following food items is obtained from the STEM of a plant?
(a) Carrot  (b) Potato  (c) Spinach  (d) Cauliflower

Accepted Answer

Potato is a modified underground stem (a stem tuber) that stores food and sprouts new shoots from its 'eyes' — a capability true roots do not have.

Answer: (b) Potato. Trap (a) Carrot is a root, not a stem — a common source of confusion since potato also grows underground and is often wrongly grouped with it. Trap (c) Spinach is a leaf. Trap (d) Cauliflower is an unopened flower cluster, not a stem.

Question 2

A child's diet consistently lacks Vitamin A. This deficiency is most likely to cause:
(a) Beriberi  (b) Scurvy  (c) Night blindness  (d) Rickets

Accepted Answer

Vitamin A deficiency specifically impairs vision in dim light, a condition known as night blindness, along with causing dry skin.

Answer: (c) Night blindness. Trap (a) Beriberi results from Vitamin B1 deficiency. Trap (b) Scurvy results from Vitamin C deficiency. Trap (d) Rickets results from Vitamin D deficiency — all four are genuine deficiency diseases from this chapter's table, but only one matches Vitamin A specifically.

Question 3

In the iodine test for starch, a positive result is indicated by:
(a) The solution turning pink  (b) The formation of a blue-black colour  (c) The sample turning violet  (d) An oily, translucent patch forming

Accepted Answer

Dilute iodine solution added to a starch-containing food produces a characteristic blue-black colour — the standard, specific indicator used in NCERT's classroom test.

Answer: (b) Blue-black colour. Trap (a) is not a recognised result for any of the three standard food tests. Trap (c) violet is the positive result for the protein (Biuret) test, not starch — a frequently swapped pair. Trap (d) an oily translucent patch is the positive result for the fat test, not starch.

Question 4

Which of the following best explains why refrigeration preserves food but does not make it last indefinitely?
(a) It kills all microorganisms instantly  (b) It slows down the growth and activity of microorganisms without killing them  (c) It removes all moisture from the food  (d) It permanently changes the chemical composition of the food

Accepted Answer

Low temperature slows microbial metabolism and reproduction considerably, but the microorganisms already present remain alive and will eventually multiply enough to spoil the food — refrigeration buys time, it does not sterilise.

Answer: (b). Trap (a) is the common misconception that refrigeration 'kills germs' — it does not. Trap (c) confuses refrigeration with drying/dehydration, a different preservation method entirely. Trap (d) wrongly implies preservation works by altering the food's chemistry, when refrigeration is a purely physical, temperature-based method.

Question 5

Which pair correctly matches a component of food with its primary function?
(a) Fats — protective food  (b) Proteins — body-building food  (c) Vitamins — energy-giving food  (d) Carbohydrates — body-building food

Accepted Answer

Proteins are specifically the body-building nutrient, essential for growth, tissue repair, and forming enzymes and antibodies.

Answer: (b). Trap (a) mislabels fats, which are actually a concentrated energy-giving component, not a protective one. Trap (c) mislabels vitamins, which are protective, not energy-giving. Trap (d) mislabels carbohydrates, which are energy-giving, not body-building — all three traps swap a component into the wrong one of the three broad functional categories.

Question 6

Roughage in our diet mainly helps by:
(a) Providing a concentrated source of energy  (b) Building and repairing body tissue  (c) Adding bulk to food and preventing constipation  (d) Supplying essential vitamins and minerals

Accepted Answer

Roughage (dietary fibre) is not digested or absorbed and contributes no nutrients or energy, but it adds bulk to food and aids peristalsis, which prevents constipation — its value is purely mechanical.

Answer: (c). Trap (a) wrongly assigns roughage an energy-giving role it does not have, since it is not digested. Trap (b) confuses roughage's role with protein's body-building function. Trap (d) wrongly treats roughage as a vitamin/mineral source, when it is a distinct, non-nutrient component of food.

Question 7

A student adds two drops of copper sulphate solution followed by ten drops of caustic soda (sodium hydroxide) solution to a food sample, and the sample turns violet. The food most likely contains a high proportion of:
(a) Starch  (b) Fat  (c) Protein  (d) Roughage

Accepted Answer

Copper sulphate followed by sodium hydroxide turning a sample violet is the Biuret test's specific positive result for protein.

Answer: (c) Protein. Trap (a) starch is tested with iodine solution, not copper sulphate/sodium hydroxide. Trap (b) fat is tested using the paper-translucency method, an entirely different procedure. Trap (d) roughage has no standard colour-change test at this level; it is a distractor with no matching procedure in this chapter.

Question 8

A Class VI teacher wants students to discover, through their own observation, which everyday foods contain starch, protein, and fat, rather than simply reading the facts from the textbook. Which approach best reflects NCF 2005's recommended pedagogy for this topic?
(a) Reading the relevant textbook page aloud and asking students to underline key terms  (b) Conducting the iodine, Biuret, and fat-translucency tests as a hands-on classroom activity so students record and infer results themselves  (c) Assigning the chapter as homework followed by a short dictation test  (d) Showing a video of the tests being performed by someone else, without students handling any materials

Accepted Answer

NCF 2005's constructivist, activity-based approach specifically calls for learners to personally test real food samples and draw conclusions from their own recorded observations, rather than receiving the conclusion secondhand in any form.

Answer: (b). Trap (a) and trap (c) are both textbook-centred, passive methods that skip direct experimentation entirely. Trap (d) is the closest distractor — it does show the actual experiment — but students never handle the materials themselves, which is precisely the hands-on element NCF 2005 treats as essential, not optional.

Question 9

A student remarks, 'Since fat is bad for health, foods like ghee and nuts should be completely avoided.' As a Science teacher applying NCERT's balanced-diet framework, the most appropriate correction is to explain that:
(a) The student is entirely correct — all fats should be eliminated from the diet  (b) Fats are one of the six essential components of food and are needed in moderate amounts as a concentrated energy source, so complete avoidance is not advisable  (c) Fats should be replaced entirely with extra protein for a healthier diet  (d) Only fats from animal sources are harmful; plant-based fats are not real nutrients

Accepted Answer

The correct teaching response affirms fat's genuine, necessary role — concentrated energy and enabling absorption of fat-soluble vitamins — while steering the student toward moderation rather than either extreme.

Answer: (b). Trap (a) endorses the very misconception the teacher is meant to correct. Trap (c) invents an unsupported dietary substitution not grounded in the balanced-diet concept. Trap (d) invents a false animal-fat-versus-plant-fat distinction that has no basis in this chapter's content.

Question 10

Two students disagree: one says vitamins and minerals are 'basically the same protective nutrients,' the other insists they are chemically distinct. Which statement should a Class VII/VIII Science teacher use to resolve this?
(a) They are indeed identical categories, and the distinction is only a naming convention  (b) Vitamins are organic compounds required in small quantities, while minerals are inorganic elements obtained from soil and water via food — both are protective, but chemically distinct  (c) Minerals are a type of vitamin found only in animal-based foods  (d) Vitamins are needed only by children, while minerals are needed only by adults

Accepted Answer

The scientifically accurate resolution affirms that vitamins (organic compounds) and minerals (inorganic elements) are functionally similar (both protective) but chemically distinct categories, each with its own deficiency diseases.

Answer: (b). Trap (a) directly restates the misconception the teacher is meant to correct, rather than resolving it. Trap (c) invents a false subset relationship between minerals and vitamins. Trap (d) invents an age restriction that has no basis in this chapter — both vitamins and minerals are needed across all ages.

Practice — "Science — Food"

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