It is a well-known fact that trees and plants are also living beings like humans. They need food, water and air for survival. It is interesting to know how they make their food. Plants derive their food both from the earth and the air. If you minutely observe their roots, you will find that the ends of these roots are like fibres, also called root hairs. They absorb water and minerals and transport them upwards to the leaves through the trunk and the branches. It is the leaves which make the food for the plant. Leaves have pores that are filled with air. They also have a green colouring matter called chlorophyll. This chlorophyll acts as a catalyst; it uses carbon dioxide from the air and the hydrogen from the water present in the leaves, to make carbohydrates (sugars) using sunlight as energy. This process is called photosynthesis. In this process, oxygen and water are the by-products, which are released by the leaves of the plants. Sugar is further converted into starch. From these carbohydrates, the plants can build complex substances as foods, which it needs for its life and growth. These substances include proteins, juices, oils (fats), etc. The water from which the plants take hydrogen for photosynthesis contains dissolved minerals required for building various parts of the plant body. These are compounds of nitrogen, sulphur, phosphorus, sodium, calcium, magnesium, iron, etc. Food which is not immediately needed for growth is stored in the plant including its seeds, fruits, tubers or bulbs. On germinating, the new shoot uses the food that is accumulated in the seed.