NCERT Solutions class 7 Science 2. Nutrition in Animals Exercise (NCERT Text Book)

2. Nutrition in Animals

Q1. Fill in the blanks:

(a) The main steps of digestion in humans are __________, __________, __________, _________ and __________.

Ans: ingestion, digestion, absorption, assimilation, egestion

(b) The largest gland in the human body is __________.

Ans: Liver

(c) The stomach releases hydrochloric acid and ___________ juices which act on food.

Ans: gastric

(d) The inner wall of the small intestine has many finger-like outgrowths called _________.

Ans: Villi.

(e) Amoeba digests its food in the ____________ .

Ans : Food vacules

Q2. Mark ‘T’ if the statement is true and ‘F’ if it is false:

(a) Digestion of starch starts in the stomach. (T/F)

(b) The tongue helps in mixing food with saliva. (T/F)

(c) The gall bladder temporarily stores bile. (T/F)

(d) The ruminants bring back swallowed grass into their mouth and chewit for some time. (T/F)

Ans:

(a)    F

(b)    T

(c)    T

(d)    T

Q3. Tick ( ) mark the correct answer in each of the following:

(a) Fat is completely digested in the

(i)  stomach  (ii)  mouth    (iii) small intestine   (iv)  large intestine

Ans: (iii) Small intestine

(b) Water from the undigested food is absorbed mainly in the

(i)  stomach  (ii)   foodpipe  (iii)  small intestine  (iv) large intestine

Ans: (iv) Large intestine

Q4. Match the items of Column I with those given in Column II:

Ans:

Q5. – What are villi? What is their location and function?

Ans:– Many small finger-like outgrowths are situated in the inner walls of small intestine, these are called villi.

Functions: The villi increase the surface area for absorption of the digestive food.

Q6. – Where is the bile produced? Which component of the food does it digest?

Ans:– The bile produced in liver.  It is responsible for complete digestion of fats

Q8. Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.

Ans: cellulose is a type of carbohydrate that can be digested by ruminants but not by humans.

(i) Ruminants have a large sac-like structure between the small intestine and large intestine while human have no so.

(ii) The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.

Q9. Why do we get instant energy from glucose?

Ans: Glucose is the simplest form of carbohydrate. It is absorbed very quickly without taking part in any process  and give instant energy to the body.

Q10. Which part of the digestive canal is involved in:

(i) absorption of food ________________.

(ii) chewing of food ________________.

(iii) killing of bacteria ________________.

(iv) complete digestion of food ________________.

(v) formation of faeces ________________.

Ans:

(i) Small Intestine

(ii) Buccal cavity

(iii) Stomach

(iv) Small intestine

(v) Large intestine

Q11. Write one similarity and one difference between the nutrition in amoeba and human beings.

Ans:

Similarity: Both take digestion and use digestive juice to digest food.

Difference: Human need to chew food, whereas in amoeba there is no chewing.

Q12. Match the items of Column I with suitable items in Column II

Ans: