NCERT Class X Science Class: Chapter –6. Life Processer – Part-9

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Question 48:

Differentiate between an artery and a vein.

Answer:

Differentiate between an Artery and a Vein.
Differentiate between an artery and a vein.

Artery

Vein

1

Have thick elastic, muscular walls.

1

Have thin, non-elastic, walls.

2

Lumen is narrow

2

Lumen is wide

3

Carry blood from heart to all body parts.

3

Carry blood from form all body part to heart.

4

Carry oxygenated blood (except pulmonary artery)

4

Carry deoxygenated blood (except pulmonary vein).

Question 49:

What are the adaptations of leaf for photosynthesis?

Answer:

(a) Leaves provide large surface area for maximum light absorption.

(b) Leaves are arranged at right angles to the light source in a way that causes overlapping.

(c) The extensive network of veins enables quick transport of substances to and from the mesophyll cells.

(d) Presence of numerous stomata for gaseous exchange.

(e) The chloroplasts are more in number on the upper surface of leaves.

Image Figure shown the leaf parts

Image Figure Shown the Leaf Parts

Image Figure shown the leaf parts

Question 50:

Why is small intestine in herbivores longer than in carnivores?

Answer:

Digestion of cellulose takes a longer time. Hence, herbivores eating grass need a longer small intestine to allow complete digestion of cellulose. Carnivorous animals cannot digest cellulose, hence they have a shorter intestine.

Image Figure shown the adaptations

Image Figure Shown the Adaptations

Image Figure shown the adaptations

Question 51:

What will happen if mucus is not secreted by the gastric glands?

Answer:

Gastric glands in stomach release hydrochloric acid, enzyme pepsin and mucus. Mucus protects the inner lining of stomach from the action of hydrochloric acid and enzyme pepsin. If mucus is not released, it will lead to erosion of inner lining of stomach, leading to acidity and ulcers.

Question 52:

What is the significance of emulsification of fats?

Answer:

Fats are present in food in the form of large globules which makes it difficult for enzymes to act on them. Bile salts present in bile break them down mechanically into smaller globules which increases the efficiency of fat digesting enzymes.

Image Figure shown the emulsification of fat

Image Figure Shown the Emulsification of Fat

Image Figure shown the emulsification of fat

Question 53:

What causes movement of food inside the alimentary canal?

Answer:

The wall of alimentary canal contains muscle layers. Rhythmic contraction and relaxation of these muscles pushes the food forward. This is called peristalsis, which occurs all along the gut.

Image food inside the alimentary canal

Image Food Inside the Alimentary Canal

Image food inside the alimentary canal

Question 54:

Why does absorption of digested food occur mainly in the small intestine?

Answer:

Maximum absorption occurs in small intestine because

(a) Digestion is completed in small intestine

(b) Inner lining of small intestine is provided with villi which increases the surface area for absorption.

(c) Wall of intestine is richly supplied with blood vessels (which take the absorbed food to each and every cell of the body).

Image the small intestine

Image the Small Intestine

Image the small intestine