During photosynthesis, which of the following is absorbed by green plants?

Concept

Photosynthesis is the process by which green plants use light energy captured by chlorophyll to make carbohydrates.

Its raw materials are carbon dioxide from the air and water; oxygen is formed and released as a by-product.

Application

Carbon dioxide enters the leaf mainly through stomata and supplies the carbon used to form glucose. Therefore, among the given substances, green plants absorb carbon dioxide during photosynthesis.

Contrast

• Helium is inert and is not a raw material for photosynthesis.

• Nitrogen supports plant growth after uptake mainly as nitrate or ammonium ions, but nitrogen gas is not a photosynthetic raw material.

• Oxygen is mainly produced during photosynthesis, although plants also use it in respiration.

Cross-check

The word equation is: carbon dioxide + water → glucose + oxygen (in the presence of light and chlorophyll). Carbon dioxide is on the reactant side, confirming that it is taken in.