NCERT 7th Class (CBSE) Science: Nutrition in Animals

Question: Explain the process rumination.

Answer: The grass eating animals chewing continuously even where they are not eating grass. They store the grass in a separate part of the stomach. This part is called rumen. Here the food gets partially digested and is called cud. Later the cud return in the mouth and animal chews it again. This process is called rumination and the animals are the called ruminants.

Question: Why have the ruminants developed the habit of  ”Chewing cud.” ?

Answer: The ruminants developed the habit of chewing the cud for there safety. As these animals are eaten away by carnivores, so to avoid being caught by carnivores, they quickly swallow their food and go to a safe place. Then they bring back the swallowed food to their mouth and chew it again.

Question: What is the importance of transport of materials in the body of multi cellular organisms?

Answer: The importance of transport of materials in the body of multi cellular organisms is as follows:

1. In the body of multi cellular organisms the transport plays an important role. The food material, water and oxygen are to be supplied to every cell  of all the part of the body to get energy for proper functioning.
2. The metabolic wastes produced in all the part of the body are to be secreted out from the body so that the whole body part may function properly.

For all the above mentioned functions, transport is the only source. So it is important for the body of multi cellular organisms.

Question: Why is the process of excretion important for living organisms?

Answer: In all the living being the metabolic activities take place within the body for getting energy. The remaining part of the food is called as the waste material which are harmful to the body. So to become healthy and for proper functioning it is essential to pass these wastes from the body.

Question: What are the main organs of the digestive system in our body?

Answer: The process of digestion starts in the mouth. From the mouth, the food passes through a foodcanal (called alimentary canal). Alimentary canal is a long, muscular and coiled tube. It start from the mouth and ends at anus.

The different organs of the alimentary canal are as follows:

1. Mouth and mouth cavity.
2. Oesophagus (gullet or food pipe)
3. Stomach.
4. Small intestine.
5. Large intestine.
6. Anus.

Associated with the alimentary canal are some glands. These are: Salivary glands, Liver, Pancreas. The alimentary canal along with the associated glands is called the digestive system.