CBSE Class 10 Science Life Processes VBQs Set 07

A & R Questions

Question. Assertion : In some animals like amphibians, the first step of gaseous exchange occurs through body surface.
Reason : Body surface or membrane of amphibians is thick in nature.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Answer: (c) Assertion is correct statement but reason is wrong statement.

Question. Assertion : Transpiration lowers down plant temperature.
Reason : Transpiration reduces the concentration of mineral salts.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Answer: (c) Assertion is correct statement but reason is wrong statement.

Multiple Choice Questions

Question. Stomach of man mainly digests
(a) carbohydrates
(b) proteins
(c) fat
(d) sucrose.
Answer: (b) proteins

Question. Which is the correct sequence of air passage during inhalation?
(a) Nostrils \( \to \) larynx \( \to \) pharynx \( \to \) trachea \( \to \) lungs
(b) Nasal passage \( \to \) trachea \( \to \) pharynx \( \to \) larynx \( \to \) alveoli
(c) Larynx \( \to \) nostrils \( \to \) pharynx \( \to \) lungs
(d) Nostrils \( \to \) pharynx \( \to \) larynx \( \to \) trachea \( \to \) alveoli
Answer: (d) Nostrils \( \to \) pharynx \( \to \) larynx \( \to \) trachea \( \to \) alveoli

Question. Opening and closing of stomata is due to
(a) pressure of gases inside the leaves
(b) changes of turgor pressure in guard cells
(c) effect of hormones
(d) their genetic constitution.
Answer: (b) changes of turgor pressure in guard cells

Question. Glomerular filtration is possible because
(a) afferent arteriole has less diameter than the efferent arteriole
(b) afferent arteriole has more diameter than the efferent arteriole
(c) both have the same diameter
(d) afferent capillaries have more diameter than efferent capillaries.
Answer: (b) afferent arteriole has more diameter than the efferent arteriole

Question. Which of the following has no muscular walls?
(a) Artery
(b) Arteriole
(c) Capillary
(d) Vein
Answer: (c) Capillary

VSA Type Questions

Question. Give one example of each plant and animal which shows parasitic nutrition.
Answer: Parasitic plant: Cuscuta (Amarbel). Parasitic animal: Tapeworm / Plasmodium / Leech.

Question. What is the function of bile?
Answer: 1. It neutralizes the acidity of food coming from the stomach and makes it alkaline for pancreatic enzymes to act. 2. Bile salts emulsify fats by breaking down large fat globules into smaller ones.

Question. Which blood cells help in preventing blood loss at the site of injury?
Answer: Platelets.

Question. What kind of nutrition occurs in fungi?
Answer: Saprophytic nutrition (they break down organic matter outside the body and absorb it).

SA I Type Questions

Question. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Answer: Mammals and birds are warm-blooded animals that require high amounts of energy to maintain a constant body temperature. Separation of blood ensures a highly efficient supply of oxygen to the body cells to meet this high energy demand.

Question. Differentiate between excretion and egestion.
Answer: Excretion is the removal of metabolic toxic nitrogenous wastes produced inside cells (like urea), whereas egestion is the removal of undigested and unabsorbed food from the alimentary canal through the anus.

Question. What happens to the rate of breathing during vigorous exercise and why?
Answer: The rate of breathing increases during vigorous exercise. This is because muscles require more energy, which demands more oxygen for the rapid oxidation of food. Increased breathing helps intake more oxygen and remove the excess carbon dioxide produced.

Question. What are the components of the transport system in highly organised plants?
Answer: The components are Xylem (transports water and minerals from roots to leaves) and Phloem (transports products of photosynthesis from leaves to other parts of the plant).

Question. What is the function of digestive enzymes?
Answer: Digestive enzymes act as biological catalysts that break down complex, large, and insoluble food molecules into simple, small, and soluble molecules so they can be absorbed into the bloodstream.

Question. What is emulsification? Name the organ where fat is emulsified in the alimentary canal of human beings.
Answer: Emulsification is the breakdown of large fat globules into smaller globules by the action of bile salts. This process occurs in the small intestine.

SA II Type Questions

Question. Give reasons for the following: (i) Lungs always contain residual volume. (ii) Nostrils are lined with mucus.
Answer: (i) Lungs contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for carbon dioxide to be released between inhalation and exhalation. (ii) Mucus in the nostrils helps in filtering the inhaled air by trapping dust, dirt, and pathogens before they reach the lungs.

Question. Describe double circulation in human beings. Why is it necessary?
Answer: In humans, blood flows through the heart twice during one cycle. It involves Pulmonary Circulation (Heart \( \to \) Lungs \( \to \) Heart) and Systemic Circulation (Heart \( \to \) Body organs \( \to \) Heart). It is necessary to prevent the mixing of oxygenated and deoxygenated blood, ensuring an efficient oxygen supply to maintain high energy levels and body temperature.

Question. Give five functions of blood.
Answer: 1. Transport of oxygen to tissues. 2. Transport of carbon dioxide to lungs. 3. Transport of digested food. 4. Transport of hormones. 5. Protection against diseases (WBCs).

Question. “Fishes show single circulation”. Explain.
Answer: In fish, the heart is two-chambered. Deoxygenated blood is pumped to the gills for oxygenation and then flows directly to the rest of the body before returning to the heart. Thus, blood passes through the heart only once in one complete circuit.

Question. Leaves of a healthy potted plant were coated with vaseline to block the stomata. Will this plant remain healthy for long? State three reasons for your answer.
Answer: No, the plant will not remain healthy. Reasons: 1. Photosynthesis will stop because \( CO_2 \) cannot enter. 2. Transpiration will stop, affecting the upward movement of water and minerals. 3. Respiration (gaseous exchange) will be hindered.

Question. How can you design an experiment to demonstrate that sunlight is essential for photosynthesis?
Answer: 1. Destarch a potted plant by keeping it in the dark for 2-3 days. 2. Partially cover one leaf on both sides with black paper. 3. Expose the plant to sunlight for 4-6 hours. 4. Pluck the leaf and test for starch with iodine. Result: The covered part remains pale (no starch), while the exposed part turns blue-black (starch present), proving sunlight is essential.

LA Type Questions

Question. (a) What are the functions of stomach? (b) What are the constituents of gastric juice? Write one function of each.
Answer: (a) Stomach stores food, churns it, and begins protein digestion. (b) 1. Hydrochloric Acid: Makes medium acidic for pepsin and kills bacteria. 2. Pepsin: Digests proteins into peptones. 3. Mucus: Protects inner lining of stomach from HCl.

Question. (a) Write three modes of heterotrophic nutrition. Also give examples in each case. (b) Name the two glands associated with the digestive system in humans. Name their secretion.
Answer: (a) 1. Holozoic (Amoeba, Human). 2. Saprophytic (Mushroom, Yeast). 3. Parasitic (Cuscuta, Lice). (b) Liver (secretes bile) and Pancreas (secretes pancreatic juice).

Question. How are oxygen and carbon dioxide transported in human beings?
Answer: Oxygen is primarily carried by hemoglobin in Red Blood Cells as oxyhemoglobin. Carbon dioxide is more soluble in water and is mainly transported in the dissolved form in the blood plasma (as bicarbonate) and a small part by hemoglobin.