Class 7 Science · Original EZT practice
Life Processes in Animals (Class 7 Chapter 9): summary and practice
Food becomes energy, and the body needs oxygen to use it. Chapter 9 follows food through the human digestive system, then breathing, and compares how other animals do both. All questions are original EZT tutor practice following the chapter's own section order. Edition note: this page covers the new NCERT book Curiosity (Grade 7). Older Class 7 books numbered chapters differently - check your chapter title, not just the number.
8 original worked examples, 8 fresh self-check questions and 4 mixed questions, with explained answers. These are not copied textbook exercises, an official chapter index or a full answer key. No affiliation with NCERT is claimed.
Official sources for topic and edition context, checked 20 October 2026:
1. Nutrition and digestion in humans
Digestion breaks food into simple substances the body can absorb. Food travels through the mouth, oesophagus, stomach, small intestine and large intestine. Saliva in the mouth begins digestion - it breaks starch in chewed rice into simple sugars; the stomach churns food; digestion finishes and nutrients are absorbed in the small intestine; the liver (bile) and pancreas help; the large intestine takes back water.
2. Do all animals digest the same way?
Digestive systems differ with food and body: a tube from mouth to anus in humans, simpler cavities in smaller animals. Ruminants such as cows, which eat grass, have a different arrangement from humans. The pattern - take in food, digest, absorb, remove waste - is shared.
3. Respiration in humans
We breathe in air through the nose, down the windpipe into the lungs, which hold tiny air sacs called alveoli where oxygen enters the blood and carbon dioxide leaves. The diaphragm and rib movement pull air in and push it out.
4. How other animals breathe
Fish breathe through gills that take oxygen dissolved in water; earthworms breathe through their moist skin.
Choose, solve, check, then try a fresh question.
Before calculating, read the method prompt and name the condition that makes it useful. Write your own attempt. Open the steps only when you need them, and use the check to catch a wrong sign, unit or interpretation. Finish with the fresh question before reading its answer.
Order the organs food passes through
Choose the method: Follow a bite of food from the mouth onward.
EZT practice question
Arrange in order: stomach, mouth, small intestine, oesophagus, large intestine.
Show the worked solution
- Food enters at the mouth.
- It travels down the oesophagus to the stomach.
- Then the small intestine, and finally the large intestine.
Answer: Mouth, oesophagus, stomach, small intestine, large intestine.
Check: The order follows the real path of food through the body.
Watch for this: Do not place the stomach before the oesophagus; food reaches the stomach through it.
Now try it yourself
Which juice in the mouth begins digestion?
Check your answer
Saliva.
Saliva starts breaking starch into simple sugars.
Name where most food is absorbed
Choose the method: Ask where digestion finishes and nutrients pass into the blood.
EZT practice question
Where is most food absorbed?
Show the worked solution
- Digestion finishes in the small intestine.
- Its inner surface is built to absorb nutrients into the blood.
Answer: The small intestine.
Check: Absorption follows completed digestion, which happens in the small intestine.
Watch for this: Do not say the stomach; it mainly churns and partly digests food.
Now try it yourself
Which organ absorbs water from undigested food?
Check your answer
The large intestine.
The large intestine takes back water before waste leaves the body.
Define egestion
Choose the method: Name the step that removes what the body could not digest.
EZT practice question
What is egestion?
Show the worked solution
- Some food parts stay undigested.
- The body must remove this waste.
- That removal is egestion.
Answer: The removal of undigested waste from the body.
Check: Egestion is the last step of the nutrition pattern.
Watch for this: Do not confuse egestion with excretion; egestion removes undigested food, not cell waste.
Now try it yourself
Name the process of removing undigested waste.
Check your answer
Egestion.
That is the term the chapter uses for this step.
Explain why digestive systems differ between animals
Choose the method: Link the system to the food it must handle.
EZT practice question
Why do grass-eaters have different digestive systems from meat-eaters?
Show the worked solution
- Grass is harder to digest than meat.
- Breaking it down needs a different arrangement, as in ruminants like cows.
- So the systems differ with the food.
Answer: Their food differs in how hard it is to digest, so the digestive systems differ.
Check: The explanation ties the body plan to the diet.
Watch for this: Do not say one system is simply better; each fits its own food.
Now try it yourself
Name one common step of nutrition in all animals.
Check your answer
Any of: taking in food, digestion, absorption, removing waste.
The overall pattern is shared even when the organs differ.
Order the parts air passes through
Choose the method: Follow one breath from the nose to the air sacs.
EZT practice question
Put in order: alveoli, nose, lungs, windpipe.
Show the worked solution
- Air enters through the nose.
- It passes down the windpipe into the lungs.
- Inside the lungs it reaches the alveoli.
Answer: Nose, windpipe, lungs, alveoli.
Check: The order follows the real path of air into the body.
Watch for this: Do not place the alveoli before the lungs; they are tiny sacs inside the lungs.
Now try it yourself
Where does gas exchange happen?
Check your answer
In the alveoli.
Oxygen enters the blood and carbon dioxide leaves at the alveoli.
Explain the diaphragm's role in breathing in
Choose the method: Watch what moves when the chest expands.
EZT practice question
What happens to the diaphragm when we breathe in?
Show the worked solution
- Breathing in needs space for air in the lungs.
- The diaphragm moves down and the ribs lift, so the chest expands.
- Air is drawn in to fill the space.
Answer: It moves down and the chest expands, drawing air in.
Check: The downward movement makes room, and air follows.
Watch for this: Do not say the diaphragm pushes air in; it makes space so air flows in.
Now try it yourself
Which gas enters the blood during breathing?
Check your answer
Oxygen.
Oxygen passes into the blood at the alveoli while carbon dioxide leaves.
Describe how a fish breathes
Choose the method: Ask what oxygen source water animals use and which organ takes it.
EZT practice question
How does a fish breathe?
Show the worked solution
- Water holds dissolved oxygen.
- The fish's gills take that oxygen from the water passing over them.
Answer: Through gills, which take dissolved oxygen from the water.
Check: The organ (gills) and the oxygen source (dissolved in water) are both named.
Watch for this: Do not say fish breathe air like we do; they use oxygen dissolved in water.
Now try it yourself
Which organs do fish use for breathing?
Check your answer
Gills.
Gills are the fish's breathing organs.
Explain why an earthworm's skin must stay moist
Choose the method: Gases must dissolve before they can pass through skin.
EZT practice question
Why must an earthworm's skin stay moist?
Show the worked solution
- The earthworm breathes through its skin.
- Gases pass through only after dissolving in moisture on the skin.
- Dry skin would block breathing.
Answer: Gases dissolve in the moisture and pass through the skin, so it must stay moist.
Check: The answer links moisture to the passage of gases.
Watch for this: Do not say moisture keeps the worm cool; the reason is breathing.
Now try it yourself
Name the breathing surface of an earthworm.
Check your answer
Its moist skin.
The whole skin surface exchanges gases when moist.
Try a mixed set
Choose a method or explanation before opening each answer.
1. What is the path of food in humans?
Show answer and reason
Mouth, oesophagus, stomach, small intestine, large intestine.
Digestion and absorption happen along this route.
2. Where does digestion finish and food get absorbed?
Show answer and reason
In the small intestine.
Its surface passes nutrients into the blood.
3. What are alveoli?
Show answer and reason
Tiny air sacs in the lungs where oxygen enters the blood and carbon dioxide leaves.
They are the gas-exchange surface.
4. How do fish breathe?
Show answer and reason
Through gills, using oxygen dissolved in water.
Gills extract dissolved oxygen as water flows over them.
Try it yourself
Work these on paper before checking any notes. Answers are deliberately not shown here.
- Chew plain rice for a minute without swallowing - what taste appears and why?
- Explain why the small intestine, not the stomach, is called the main site of absorption.
- Compare how a fish and an earthworm get their oxygen.
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Questions about this practice page
- What is the path of food in humans?
- Mouth, oesophagus, stomach, small intestine, large intestine.
- Where does digestion finish and food get absorbed?
- In the small intestine.
- What are alveoli?
- Tiny air sacs in the lungs where oxygen enters the blood and carbon dioxide leaves.
- How do fish breathe?
- Through gills, using oxygen dissolved in water.
- Are these the NCERT exercise questions for Life Processes in Animals?
- No. EZT pages are original practice following the chapter's section order - use them to prepare for the textbook exercises, not as a substitute for your book.