NCERT Class VII Science Solutions: Chapter 2-Nutrition in Animals Part 5

Download PDF of This Page (Size: 195K)

Question 23:

Ruminants such as cows and buffaloes swallow their food hurriedly and then sit restfully and chew their food. Can you reason why?

Answer:

Ruminants such as cows and buffaloes swallow their food hurriedly and store it in part of the stomach called rumen. The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.

Later, this partially digested food is returned to the buccal cavity of the animals in small lumps and animal chews it sitting restfully to complete the process of digestion. This process is called rumination. The thoroughly chewed cud is swallowed again to other compartment of stomach and then into small intestine for complete digestion and absorption.

Question 24:

Boojho and Paheli were eating their food hurriedly so that they could go out and play during the recess. Suddenly, Boojho started coughing violently. Think of the reasons why he was coughing and discuss with your friends.

Answer:

Sometimes, when one eats hurriedly, talks or laughs while eating, the flap like valve, epiglottis closing the passage of windpipe remains open. The food may enter the wind pipe and coughing helps to clear it.

LONG ANSWER QUESTIONS

Question 25:

Fill in the blanks using the words listed below.

water, front, intestinal, salt, pseudopodia, back, vacuole

  1. The digestion of all food components is completed by the _________juice.

  2. Large intestine absorbs ________ and some_______ from the undigested food.

  3. Tongue is attached at the ___________ to the floor of the mouth cavity and is free at the _________.

  4. Amoeba pushes out __________ around the food and traps it in a food __________.

Answer:

  1. The digestion of all food components is completed by the intestinal juice.

  2. Large intestine absorbs water and some salts from the undigested food.

  3. Tongue is attached at the back to the floor of the mouth cavity and is free at the front.

  4. Amoeba pushes out pseudopodia around the food and traps it in a food vacuole.

Question 26:

Label the below given Figure, as directed below in (i) to (iv) and give the name of each type of teeth.

Image of teeth

Image of Teeth

Image of teeth

  1. The cutting and biting teeth as ‘A’

  2. The piercing and tearing teeth as ‘B’

  3. The grinding and chewing teeth as ‘C’

  4. The grinding teeth present only in adult as ‘D’

Answer:

  1. Incisors

  2. Premolars

  3. Canines

  4. Molars

Image of structure of teeth

Image of Structure of Teeth

Image of structure of teeth

Question 27:

Read the following passage carefully and answer the questions that follows it.

Bile juice is stored in a sac called, gall bladder, located near its organ of secretion, liver. The gall bladder releases the bile juice into the small intestine whenever food reaches there. Though bile Juice is devoid of any digestive enzymes, it is required for the digestion of fats. The fats cannot be digested easily because they are insoluble in water and are present as large globules. Bile juice breaks down big fat droplets into smaller droplets. These are then easily digested by the enzymes released from the pancreas.

  1. Which organ secretes the bile juice?

  2. Why is digestion of fats difficult as compared to that of other nutrients?

  3. How does bile Juice help in digestion of fat?

  4. Where is the digestion of fat completed?

  5. Does bile juice digest fat completely?

Answer:

  1. Liver

  2. Insolubility of fat in water.

  3. Breaks down big fat droplets into smaller droplets.

  4. Small Intestine

  5. No