Match the words of column A with that of column B
|Column A||Column B|
|(a) Phloem||(i) Excretion|
|(b) Nephron||(ii) Translocation of food|
|(c) Veins||(iii) Clotting of blood|
|(d) Platelets||(iv) Deoxygenated blood|
Answer: (a) → (ii), (b) → (i), (c) → (iv), (d) → (iii)
What will happen if mucus is not secreted by the gastric glands?
Answer: Mucus plays the important role of protecting the inner lining of stomach from hydrochloric acid. In case of absence of mucus, the inner lining of the stomach would be corroded by hydrochloric acid; leading to ulcers.
Differentiate between an artery and a vein.
|Have thick walls.||Have thin walls.|
|Valves absent.||Valves present.|
|Carry oxygenated blood.||Carry deoxygenated blood.|
What are the adaptations of leaf for photosynthesis?
Answer: Leaves show following adaptations for photosynthesis:
Why is small intestine in herbivores longer than in carnivores?
Answer: Cellulose forms the largest part of an herbivore’s food. Digestion of cellulose is a challenge because enzyme for that is not produced by the digestive system of the animal. Ruminant bacteria help in digestion of cellulose and they live in the gut of the herbivore. Longer small intestine ensures that the food stays for a longer duration and proper digestion could be possible. In case of carnivores, cellulose is not present in the diet; rather it is a protein rich diet. Protein can be easily digested by most of the organisms. Hence food does not need to stay longer in the digestive system of a carnivore. Due to this, the small intestine of the herbivores is longer than that of the carnivores.
What is the significance of emulsification of fats?
Answer: Fat molecules are complex. Emulsification of fat breaks the molecules into smaller parts. Thus, it becomes easy for the related enzyme to digest the fat.
Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?
Answer: Air is not available in as much quantity in water as it is in air. Aquatic animals need to put more effort to breathe in oxygen to meet their need. On the other hand, because of good availability of oxygen in the air, terrestrial animals do not need to put too much effort for breathing in. Hence, the rate of breathing is much faster in aquatic organisms than in terrestrial organisms.
Why is blood circulation in human heart called double circulation?
Answer: During one cardiac cycle, the blood passes through the heart two times. That is why, the blood circulation in human heart is called double circulation.
What is the advantage of having four chambered heart?
Answer: Presence of four chambered heart serves two purposes. First, it ensures complete segregation of oxygenated and deoxygenated blood. Second, blood is received by the upper chambers and is pumped out by the lower chambers. This segregation between received blood and sent blood increases the efficiency of the heart.
Mention the major events during photosynthesis.
Answer: The major events during photosynthesis are as follows:
In each of the following situations what happens to the rate of photosynthesis?
What causes movement of food inside the alimentary canal?
Answer: Peristalsis is a kind of movement which facilitates the movement of food inside the alimentary canal. The alternate contraction and relaxation of different parts of the alimentary canal is called peristalsis.
Why does absorption of digested food occur mainly in the small intestine?
Answer: The structure of small intestine is suited for the purpose. The ileum has lots of villi. A large number of villi serves two purposes. It increases the surface area to ensure better absorption.
Moreover, it reduces the lumen size which ensures that the food stays for longer duration in the small intestine so that proper absorption can take place. Due to this, the absorption of digested food mainly occurs in the small intestine.
Match Group (A) with Group (B)
|(a) Autotrophic nutrition||(i) Leech|
|(b) Heterotrophic nutrition||(ii) Paramecium|
|(c) Parasitic nutrition||(iii) Deer|
|(d) Digestion in food vacuoles||(iv) Green plants|
Answer:(a) → (iv), (b) → (iii), (c) → (i), (d) → (ii)
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