a) Define a nutrient. Name four important nutrients present in our food. (b) What are the various types of heterotrophic nutrition?

(a) Nutrients are the substances that provide energy to the body in building up the cells and tissues of the organism. There are two kinds of nutrients: Micronutrients (which are required in small amounts by the body) and Macronutrients (which are required in large amounts by the body). The four important nutrients present in our food are carbohydrates, fats, vitamins and minerals.

(b) The various types of heterotrophic nutrition are:

Saprophytic: The mode of nutrition in which organisms feed on dead and decaying matter. Example Fungi

Parasitic: The mode of nutrition in which organisms feed themselves by depending on host or on other living organisms. Example Leeches

Holozoic: The mode of nutrition in which the digestion of food is allowed only after the ingestion of food. Example Dogs.