4th Class Science Plants and Animals Photosynthesis

     Photosynthesis

Photosynthesis is the process by which plants make their own food. It the process of converting carbon dioxide into organic compound, especially sugar using water and sunlight. Oxygen is a by-product of this process. Photosynthesis is vital for life on earth, as it maintain the normal level of oxygen in the atmosphere. All life depends on photosynthesis directly as a source of energy or indirectly as the ultimate source of the energy in their food. Photosynthesis is also the source of carbon in all the living form. Most of the plants have green pigment called, chlorophyll, in their leaves. Chlorophyll gives the green colour of the leaf, helps in photosynthesis. It is the chlorophyll that helps the plants to trap the energy from the sunlight for making their food. Oxygen, which is produced during photosynthesis is essential for all living organisms for their survival. In the absence of photosynthesis life would be impossible on the earth.

     Air enters plants through which part?  

(a) Stem

(b) Stomata

(c) Fruit

(d) Flower

(e) Root

Answer: (b)

     The food, synthesized by the plants in the process of photosynthesis, is stored as ____.

(a) Vitamins

(b) Water

(c) Starch

(d) Both (a) and (c)

(e) None of these

Answer: (c)