What do you call the process of which plants manufacture food from water and carbon dioxide?

Carbon dioxide is present in the air, so plants just absorb it through small openings in their leaves.Plants that are submerged in water absorb carbon dioxide from the water.

Photosynthesis.

Water is obtained and absorbed by the roots of the plant. Carbon dioxide is absorbed fromt the sorrounding air.

The process is known as photosynthesis.