Which gas do plants take in during photosynthesis?

During photosynthesis, plants primarily take in carbon dioxide from the atmosphere. This process occurs in the chloroplasts of plant cells, where light energy (usually from the sun) is captured by chlorophyll, the green pigment in plants. Carbon dioxide, combined with water absorbed by the roots, undergoes a series of reactions that convert it into glucose and oxygen as byproducts. The glucose serves as an energy source for the plant, while the oxygen is released back into the atmosphere as a result of the conversion process. This play a crucial role in the Earth's ecosystem, as it helps maintain the balance of gases in the atmosphere and provides oxygen necessary for the respiration of most living organisms.