LIFE SCIENCE

Detailed explanation-1: -Gas exchange occurs in the spongy mesophyll cells that surround air spaces in the leaves. Many spongy mesophyll cells are in contact with the air spaces, providing a large surface area for gas exchange to happen.

Detailed explanation-2: -In most plants, photosynthesis occurs in special cells known as chloroplasts. The green hue we see in plants is the result of tiny grains of green pigment (light-absorbing molecules) inside the chloroplasts. These pigments are commonly known as chlorophyll (chloro=green; phyll=leaf).

Detailed explanation-3: -Because there are so many alveoli ( 300 million per lung) within each alveolar sac and so many sacs at the end of each alveolar duct, the lungs have a sponge-like consistency. This organization produces a very large surface area that is available for gas exchange.