In Class VI you learnt that food is essential for all living organisms.
You also learnt that carbohydrates, proteins, fats, vitamins and minerals are components of food. These components of food are necessary for our body and are called nutrients.
All living organisms require food. Plants can make their food themselves but animals including humans cannot. They get it from plants or animals that eat plants. Thus, humans and animals are directly or indirectly dependent on plants.
MODE OF NUTRITION IN PLANTS:
Plants are the only organisms that can prepare food for themselves by using water, carbon dioxide and minerals. The raw materials are present in their surroundings.
Living organisms to build their bodies, to grow, to repair damaged parts of their bodies and provide the energy to carry out life processes.
Nutrition is the mode of taking food by an organism and its utilisation by the body. The mode of nutrition in which organisms make food themselves from simple substances is called autotrophic (auto = self; trophos = nourishment) nutrition.
Therefore, plants are called autotrophs. Animals and most other organisms take in ready made food prepared by the plants. They are called heterotrophs (heteros = other).
Boojho wants to know how plants prepare their own food. Now we may ask where the food factories of plants are located: whether food is made in all parts of a plant or only in certain parts? How do plants obtain the raw materials from the surroundings? How do they transport them to the food factories of the plants?