The element necessary for photosynthesis in plants is carbon dioxide (CO2). During photosynthesis, plants absorb carbon dioxide from the atmosphere through tiny openings called stomata and take in sunlight through chlorophyll in their leaves. This process combines carbon dioxide and water (H2O) to produce glucose (a sugar) and oxygen (O2). The glucose provides energy for the plant’s growth and metabolism, while oxygen is released as a by-product, which is essential for the survival of most living organisms on Earth.