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Class 7 Science: Life Processes in Animals, 8 practice questions with answers

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These are 8 practice questions on Class 7 Science Chapter 9, Life Processes in Animals, of the new NCERT textbook, Curiosity. Each has a worked answer and the textbook page it comes from. They cover what bile and the stomach's mucus do, how the small intestine absorbs food, why fibre matters, how a sparrow and a cow break down their food, how a frog and an earthworm exchange gases, the diaphragm, and the word equation for respiration. Try each one before you open the answer.

These questions are our own, drafted with AI help, and every answer was checked against the textbook page it cites, but no practising teacher has reviewed them yet. If you find a mistake, please tell us.

What the chapter says you need

Facts from the NCERT textbook (Curiosity: Textbook of Science for Grade 7, Chapter 9, printed pages 121 to 136):

Digestion

Question 1. Ria says, "Bile from the liver digests the proteins in our food." Find her mistake.

Answer: bile does not break down proteins; it neutralises acids and breaks fats into tiny droplets. Bile, from the liver, neutralises the acid in the food coming from the stomach and breaks fats into tiny droplets, which makes their digestion easier. Proteins are broken down by the digestive juice of the stomach, by pancreatic juice and by the juice of the small intestine. (Stomach, page 125; bile and pancreatic juice, pages 125 and 126.)

Question 2. The stomach makes acid, digestive juice and mucus. What could happen to the stomach if it made no mucus?

Answer: the acid could damage the stomach's own lining. The stomach's acid helps break down proteins and kills many harmful bacteria. The mucus protects the stomach lining from the acid and prevents damage, so without it the lining would be unprotected. (Stomach, page 125.)

Question 3. Imagine two tubes of the same length. One has a smooth inner lining; the other has a thin lining covered with many finger-like projections. Which one could absorb digested food faster, and why? Which part of our body is built like it?

Answer: the one with finger-like projections, because they give it much more surface; the small intestine is built like this. The more surface the lining has, the more digested food can pass through it into the blood at the same time. The inner lining of the small intestine is thin and has thousands of finger-like projections that increase its surface area for absorption. (Absorption of nutrients, page 126.)

Question 4. Why does eating fruits, vegetables and whole grains help when stools are hard to pass?

Answer: these foods are rich in fibre, which helps the large intestine and makes the stool easier to pass. After the large intestine absorbs water and some salts from the undigested food, the semi-solid waste (stool) is stored in the rectum and passed out through the anus. Eating fibre-rich foods like fruits, vegetables and whole grains helps the large intestine work properly by making the stool easier to pass. (Large intestine and egestion, page 127.)

Different animals, different ways

Question 5. Kavya says, "A sparrow chews its grain well before swallowing it, just as a cow chews its food well before swallowing it." Find two mistakes.

Answer: a sparrow cannot chew, because birds have no teeth; and a cow does not chew its food well before the first swallow. Birds break their food down in a chamber called the gizzard, whose walls contract and relax, often with the help of grit (small stones) that the bird swallows. A cow and other grass-eating animals only partly chew the grass and swallow it; after partial digestion in the stomach, the food is brought back to the mouth and chewed again thoroughly. This is rumination. (Birds and ruminants, page 128.)

Question 6. A frog is resting under water in a pond, and an earthworm is in the soil. Through which body part does each exchange oxygen and carbon dioxide?

Answer: both use their skin. Adult frogs use lungs for breathing on land, but their skin for gas exchange when they stay in water. Earthworms use their moist skin to exchange oxygen and carbon dioxide. (Frogs, tadpoles and earthworms, page 133.)

Breathing and respiration

Question 7. Sohan says, "When I breathe in, my diaphragm moves up." Find his mistake.

Answer: the diaphragm moves down when we breathe in, and up when we breathe out. During inhalation, the ribs move up and outwards and the diaphragm, the dome-shaped muscle below the lungs, moves downwards. This increases the space inside the chest, and air enters the lungs. During exhalation, the diaphragm moves upwards and pushes air out. (Mechanism of breathing, page 130.)

Question 8. Fill in the blanks in the word equation for respiration: glucose + ______ → carbon dioxide + ______ + energy.

Answer: oxygen; water. Glucose + oxygen → carbon dioxide + water + energy. Oxygen helps break down glucose to release energy, and carbon dioxide and water are produced. (Respiration, page 132.)

Questions students ask

What is the difference between digestion and absorption? Digestion breaks complex food components into simpler forms; absorption is the passing of these digested nutrients from the small intestine into the blood, which carries them round the body. (Pages 124 and 126.)

What are alveoli? Small balloon-like sacs at the ends of the finest branches of the windpipe inside the lungs. Their thin walls are surrounded by fine tubes containing blood, and oxygen and carbon dioxide are exchanged there. (Pages 129 and 132.)

What is egestion? Removing the semi-solid waste (stool), stored in the rectum, from the body through the anus. (Page 127.)

Practise more, and check your marks

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Sources

All opened and read on 22 October 2026. Page numbers are the printed page numbers of the textbook; printed page = PDF page + 120.

The facts are from the textbook pages above. The questions and worked answers are our own. This guide is general information; follow your teacher and the textbook.