Living Science Solutions for Class 7 Science Chapter 2 Nutrition In Animals are provided here with simple step-by-step explanations. These solutions for Nutrition In Animals are extremely popular among class 7 students for Science Nutrition In Animals Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Living Science Book of class 7 Science Chapter 2 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Living Science Solutions. All Living Science Solutions for class 7 Science are prepared by experts and are 100% accurate.

Page No 22:

Question 1:

Which of these is not a part of nutrition?

(a) digestion
(b) absorption
(c) egestion
(d) excretion

Answer:

(d) excretion
Ingestion, digestion, absorption, assimilation and egestion are the five steps of nutrition. Excretion is not a part of nutrition.

Page No 22:

Question 2:

The pointed teeth in your mouth are

(a) permolars
(b) incisors
(c) molars
(d) canines

Answer:

(d) canines
The pointed teeth in our mouth are called canines. They help us in piercing and tearing the food.

Page No 22:

Question 3:

The last part of digestion of food takes place in the

(a) stomach
(b) small intestine
(c) large intestine
(d) oesophagus

Answer:

(c) small intestine
The last step of digestion of food takes place in the small intestine.

Page No 22:

Question 4:

Which of the following organs does not secrete digestive juices?

(a) stomach
(b) small intestine
(c) liver
(d) oesophagus

Answer:

(d) oesophagus
Oesophagus does not secrete any digestive juice. The stomach, small intestine and liver secrete digestive juices.

Page No 22:

Question 5:

The greatest amount of digestion of food in humans takes place in the

(a) mouth
(b) stomach
(c) small intestine
(d) large intestine

Answer:

(c) small intestine
Mostly, the digestion of food takes place in our small intestine.

Page No 22:

Question 6:

Breaking down of food into simple soluble compounds is called

(a) ingestion
(b) digestion
(c) nutrition
(d) egestion

Answer:

(b) digestion
Through the process of digestion, food is broken down into simple soluble compounds.

Page No 22:

Question 7:

During digestion, fats are changed into

(a) amino acids
(b) fatty acids and glycerol
(c) sugar
(d) glucose

Answer:

(b) fatty acids and glycerol
During digestion, fats are converted to fatty acids and glycerol.

Page No 22:

Question 8:

Bile is produced in the

(a) stomach
(b) small intestine
(c) pancreas
(d) liver

Answer:

(d) Liver
Bile is a digestive juice which is produced in the liver.

Page No 22:

Question 9:

The teeth that are used for biting an apple are

(a) incisors
(b) canines
(c) pre-molars
(d) molars

Answer:

(a) incisors
Incisors are the front teeth that are used to bite the food. Hence, we use incisors to bite an apple.

Page No 22:

Question 10:

What kind of teeth do you think are especially developed in carnivores?

(a) incisors
(b) canines
(c) pre-molars
(d) molars

Answer:

(b) canines
Carnivores have specially developed canines which help them to tear the meat.



Page No 23:

Question 1:

How does a frog catch its prey?

Answer:

 A frog catches its prey using its long and sticky tongue.

Page No 23:

Question 2:

How does a spider digest its food?

Answer:

A spider injects digestive juices into the body of its prey, which digest their body parts. Thus, a spider digests its food.

Page No 23:

Question 3:

Name the organs that make up the human alimentary canal.

Answer:

Organs that make up the human alimentary canal are mouth, pharynx, oesophagus, stomach, small intestine, large intestine and anus.

Page No 23:

Question 4:

What is the difference between milk teeth and permanent teeth?

Answer:

Milk teeth Permanent teeth
Milk teeth are twenty in number. Permanent teeth are 32 in number.
Milk teeth start falling out by the age of 6 years. Permanent teeth does not fall throughout the life until their is any deficiency.

Page No 23:

Question 5:

What is saliva and where is it produced?

Answer:

Saliva is the watery and slippery secretion produced inside the mouth.

Page No 23:

Question 6:

What is the function of taste buds?

Answer:

The function of taste buds is to detect the various tastes like sweetness, saltiness, sourness and bitterness of food.

Page No 23:

Question 7:

How long does food stay in the stomach?

Answer:

Food can stay in the stomach from a few minutes to a few hours, depending on its type. Solid food stays in the stomach for 4-5 hours, but liquid food remains only for a few minutes.

Page No 23:

Question 8:

How does the presence of acid in the stomach help?

Answer:

The acid in the stomach helps in digesting proteins. It also kills the bacteria that enter the stomach through food.

Page No 23:

Question 1:

List and explain in one sentence each, the various process involved in nutrition in animals.

Answer:

The various process involved in obtaining nutrition in animals are as follows:-
1) Ingestion- The process of taking food inside our mouth is known as ingestion.
2) Digestion- The process of breaking down food into molecules is known as digestion.
3) Absorption- The process of absorbing the digested food through the villi of small intestine is known as absorption.
4) Assimilation- The process of producing energy from the absorbed food is known as assimilation.
5) Egestion- The process of removing the wastes from our body through the anus is known as egestion.

Page No 23:

Question 2:

Explain through diagrams ingestion of food in

(a) Amoeba
(b) Hydra

Answer:

(a) Ingestion of food in Amoeba:

(b) Ingestion of food in Hydra:

Page No 23:

Question 3:

Name the four tyeps of teeth in your mouth. What are their functions?

Answer:

The four types of teeth in our mouth are:
1) Incisors- They help us in biting and cutting the food.
2) Canines- They help us in piercing and tearing the pieces of meat.
3) Premolars- They assist the molars by holding the food with their cusps and also crushing them.
4) Molars- They help us in chewing and grinding the food so that it can be swallowed easily.

Page No 23:

Question 4:

What is peristalsis? Explain with the help of a diagram.

Answer:

Peristalsis can be defined as the wave like action of the muscles of the organs present in the alimentary canal to push the food forward or downward.
 

Page No 23:

Question 5:

What is the function of

(a) saliva
(b) bile juice
(c) pancreatic juice

Answer:

(a) Saliva- It helps in breaking down the starch, present in food, into sugar. It also makes the food wet and slippery, thereby making it easier to swallow.
(b) Bile juice- It is secreted by the liver and helps in breaking down the fats, present in the food, into fatty acid and glycerol.
(c) Pancreatic juice- It is secreted by the pancreas and helps in converting starch into sugar and proteins into amino acids.

Page No 23:

Question 6:

What happens to food in the

(a) stomach
(b) small intestine

Answer:

(a) Stomach secretes acid and digestive juices that kill the bacteria, if any, present in the food. Further, the digestive juices break the proteins, present in the food, into simpler substances, thereby digesting the food partially.

(b) Small intestine also secretes some digestive juices, and also receives the bile juice secreted by the liver and the pancreatic juice secreted by the pancreas. The bile juice along with the digestive juice converts the fats into fatty acids and glycerol. The pancreatic juice breaks down the starch into sugar, and proteins into amino acid.   

Page No 23:

Question 7:

Explain how digested food is absorbed into the blood.

Answer:

The digested food is absorbed inside the small intestine which have finger like projections called villi in its inner wall. These villi comprise networks of fine blood capillaries close to their surface. The food from the villi passes into these capillaries thereby getting absorbed into the blood.

Page No 23:

Question 8:

Briefly explain the process of digestion in ruminants.

Answer:

The stomach of a ruminant is divided into four chambers. As soon as the ruminant swallows the food, it enters the first chamber called rumen where it gets partially digested (converted to cud). From here, the food enters the second chamber from where it again reaches the mouth for rumination, which is thorough chewing. The food is again swallowed, and now it enters the third and the fourth chamber for digestion. From here, it enters the small intestine for the absorption of nutrients.

Page No 23:

Question 1:

Digestion is the process of breaking down of food into simple, _________ form.

Answer:

Digestion is the process of breaking down food into simple soluble compounds.

Page No 23:

Question 2:

What is the name given to the process of using the absorbed food for producing energy?

Answer:

The process of producing energy from the absorbed food is known as assimilation.

Page No 23:

Question 3:

Name the cavity in unicellular animals in which food in present.

Answer:

In unicellular animals, food is present in the cavity called food vacuole.

Page No 23:

Question 4:

Digestion begins in the stomach. True of false?

Answer:

It is a false statement, as the digestion of food begins in the mouth.

Page No 23:

Question 5:

Saliva helps by making the food wet. It does not have any other function.True or false?

Answer:

False. Saliva not just makes the food wet, but also breaks down the starch into sugar which is easier to digest.

Page No 23:

Question 6:

Where does initial digestion of proteins take place?

Answer:

The initial digestion of proteins takes place in the stomach.

Page No 23:

Question 7:

The white hard substance that covers the teeth is called ___________

Answer:

The white hard substance covering the teeth is called enamel.

Page No 23:

Question 8:

In which part of the digestive system is water absorbed from undigested food?

Answer:

Most of the water from the undigested food is absorbed in the large intestine.

Page No 23:

Question 9:

The semi-digested food that is chewed again by ruminants is called __________

Answer:

The semi-digested food that is chewed again by ruminants is called cud.

Page No 23:

Question 10:

The function of the villi is to hold the food in the spaces between them so that food can be absorbed by the walls of the intestine.True or false?

Answer:

True. Villi are finger-like projections that hold the food in the spaces between them so that the food can be easily absorbed by the walls of the intestine.

Page No 23:

Question 1:

Which food do you think will take a longer time to get digested−sugar or beans (beans contain lot of proteins)?

Answer:

As compared to sugar, beans will take longer time for digestion, as they contain a lot of proteins. The digestion of sugar starts in the mouth, while the digestion of proteins starts in the stomach. So, the proteins of the beans will take longer time to get digested.

Page No 23:

Question 2:

Digestion needs the help of two more systems in the body to provide energy from food.
Which are these systems and how do they help?

Answer:

Two more systems which help the digestive system to provide energy to our body are the respiratory system and the cardiovascular system. The glucose absorbed in the digestive system combines with the oxygen, taken in during respiration, to form energy. These two are then transported throughout the body via blood of the cardiovascular system. 

Page No 23:

Question 3:

If you eat food while hanging upside down, do you think it will still go through the alimentary canal? Give reasons.

Answer:

Yes. Even if we eat food while hanging upside down, it will go through the alimentary canal because of the process of peristalsis. The muscles of the oesophagus will push the food downwards in a wave like action throughout the alimentary canal.



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