Life Processes in Animals — Hard

Q1. In Activity 9.1, three students place these in test tubes: A — boiled rice; B — chewed boiled rice; C — boiled, mashed potato. Each tube gets 3 mL water and a few drops of iodine. Which tubes will most likely turn blue-black?

• A. Only A
• B. A and C only
• C. Only B
• D. A, B and C

Q2. Consider the following statements about the human stomach: I. The walls of the stomach contract and relax to churn the food. II. The stomach completes the digestion of carbohydrates begun in the mouth. III. After the stomach, food has been changed into a semi-liquid mass. Which of the statements are correct?

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q3. Assertion (A): When food enters the small intestine from the stomach, bile helps to neutralise the acid in it. Reason (R): Bile is mildly basic in nature. Choose the correct option.

• A. Both A and R are true, and R is the correct explanation of A.
• B. Both A and R are true, but R is NOT the correct explanation of A.
• C. A is true, R is false.
• D. A is false, R is true.

Q4. Match the digestive secretion in Column I with the body structure that secretes it in Column II: I. Bile — (P) Pancreas II. Pancreatic juice — (Q) Liver III. Stomach acid — (R) Inner lining of the stomach Which pairing is correct?

• A. I–P, II–Q, III–R
• B. I–Q, II–P, III–R
• C. I–R, II–Q, III–P
• D. I–Q, II–R, III–P

Q5. A Class 7 student claims that food gets absorbed into the body mainly through the walls of the stomach. The best correction is that

• A. Absorption happens mainly in the mouth, due to saliva
• B. Absorption happens mainly through the inner finger-like projections of the small intestine, from where nutrients enter the blood
• C. Absorption happens mainly in the large intestine, along with water
• D. Absorption happens through the walls of the windpipe into the lungs

Q6. Consider the following statements about the large intestine: I. It is shorter than the small intestine, yet wider than it. II. It absorbs water and some salts from undigested food. III. The bacteria living inside it harm digestion and must be removed. Which of the statements are correct?

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q7. Assertion (A): The alimentary canal of a cow shows differences from that of a bird. Reason (R): Different animals have evolved variations in their alimentary canal to suit different kinds of food. Choose the correct option.

• A. Both A and R are true, and R is the correct explanation of A.
• B. Both A and R are true, but R is NOT the correct explanation of A.
• C. A is true, R is false.
• D. A is false, R is true.

Q8. A myna swallows a few small pieces of grit along with grain. The most appropriate reason from the chapter is that the grit

• A. Acts like teeth in the gizzard, helping break down food
• B. Provides essential minerals for the bird's body
• C. Cleans the inner lining of the food pipe
• D. Triggers the production of more digestive juice in the stomach

Q9. Arrange the following parts in the correct order in which air passes during inhalation: (P) Nasal passage (Q) Alveoli (R) Two lung branches (S) Windpipe (T) Nostrils The correct order is

• A. T → P → S → R → Q
• B. T → S → P → Q → R
• C. P → T → R → S → Q
• D. S → T → P → R → Q

Q10. In the bottle–Y-tube–balloon–rubber sheet model (Activity 9.2), which body parts do the balloons and the rubber sheet represent, respectively?

• A. Lungs and rib cage
• B. Lungs and diaphragm
• C. Alveoli and windpipe
• D. Diaphragm and lungs

Q11. Consider these statements about inhaled and exhaled air: I. Exhaled air contains less oxygen than inhaled air. II. Exhaled air contains more carbon dioxide than inhaled air. III. Exhaled air contains no oxygen at all. Which statements are correct?

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q12. Anil tells Sanvi that respiration and breathing are the same process. Which question by Sanvi would best help Anil correct his misunderstanding?

• A. Do animals other than humans also breathe?
• B. How many lungs does a human being have?
• C. If respiration breaks down glucose to release energy, where in the cell does this happen and how is it different from inhaling and exhaling air?
• D. Which gas turns lime water milky?

Q13. Statements about respiration in different animals: I. Tadpoles breathe through gills. II. Earthworms exchange gases through their moist skin. III. Birds breathe through gills like fish. Which statements are correct?

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q14. Three students argue: Anu — We inhale air. Shanu — We inhale oxygen. Tanu — We inhale air rich in oxygen. Who is most correct?

• A. Anu, because we breathe in whatever air is around
• B. Shanu, because oxygen is what we need
• C. Tanu, because inhaled air contains nearly 21% oxygen but is mainly other gases
• D. All three are equally correct

Q15. After their morning run, Anusha is breathing faster than Paridhi. Which TWO reasons best explain this from the chapter's logic? (i) Anusha's muscles need more oxygen to release more energy. (ii) Anusha exhales air with less carbon dioxide. (iii) Anusha's body needs to take in more oxygen and remove more carbon dioxide. (iv) Anusha's lungs have suddenly become smaller.

• A. (i) and (ii)
• B. (i) and (iii)
• C. (ii) and (iv)
• D. (iii) and (iv)