DENDROLOGY

Detailed explanation-1: -Carbon dioxide is a gas found in the air; plants can take in this gas through tiny holes in their leaves. Once they have water and carbon dioxide, they can use energy from sunlight to make their food. The leftovers from making the plant food is another gas called oxygen.

Detailed explanation-2: -For photosynthesis green plants take carbon dioxide from the air. The carbon dioxide enters the leaves of the plant through the stomata present on their surface. Each stomatal pore is surrounded by a pair of guard cells. The opening and closing of the pores of stomata is controlled by the guard cells only.