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Animals get their food from plants, either directly by eating plants or indirectly by eating animals that eat plants. Some animals eat both plants and animals. Recall that all organisms including humans require food for growth, repair and functioning of the body. Animal nutrition includes nutrient requirement, mode of intake of food and its utilisation in the body

To minimize the entropy, to maintain the body structure and its growth living being requires continuous input of energy and matter. Primary source for the both is food (or nutrient). Obtaining such substances is called nutrition.

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Nutrition is defined as a process by which living beings procure food or synthesize it and change it into a simple absorbable form by a series of biochemical processes. NCERT solutions for class 7 Science prepared by pw will help you to solve your NCERT text book exercise.

Process of Nutrition and its Examples

Animals have highly evolved digestive mechanism that includes two basic components:

1. Alimentary canal: Long, hollow, tubular structure consisting of various organs for digestion.
2. Digestive glands: They secrete enzymes / hormones which help in digestion.

Digestion in animals consists of following steps:

• Ingestion: The process of intake of food.
• Digestion: It is the breakdown of large and complex molecules into simpler, smaller and soluble forms.
• Absorption: Taking up of the digested food through intestinal wall to blood.
• Assimilation: In this process absorbed food is taken by body cells.
• Egestion: The process by which undigested matter is expelled out.

How animals take in food

The mouthparts of animals are modified to enable them to catch their prey or procure food. Examples are as follows:

• Frogs use their long tongues to catch prey.
• Butterflies and houseflies have long sucking tubes called proboscis to suck their food.
• Paramecium uses hair-like projections on its body called cilia to sweep the food into its mouth-like structure.

Also Check

1. Quiz for Class 7 Science
2. Nutrition in Animal
3. Class 7 Science Worksheet for Nutrition in Animals