What gas do plants absorb from the air?

Plants absorb carbon dioxide from the air.

During photosynthesis, plants take in carbon dioxide through tiny openings in their leaves called stomata. They also absorb water through their roots. Using energy from sunlight, chlorophyll helps the plant convert carbon dioxide and water into sugars, which provide chemical energy for growth. Oxygen is released as a by-product and usually leaves through the stomata.

This is why plants are often described as removing carbon dioxide from the atmosphere, although they also release some carbon dioxide through cellular respiration, especially at night. Over a full life cycle, a growing plant can store carbon in its leaves, stems, roots, and seeds.

Plants do not primarily absorb nitrogen gas directly from the air for photosynthesis. Nitrogen is essential for making proteins and DNA, but most plants obtain usable nitrogen compounds from soil. Nitrogen-fixing bacteria can convert atmospheric nitrogen into forms that plants can use. Oxygen, meanwhile, is mainly produced during photosynthesis rather than consumed as its main raw material.