Plants take carbon dioxide from the atmosphere mainly through their:

(iv) Leaves
Plants primarily take in carbon dioxide (CO2) from the atmosphere through their “leaves.” Specifically, the tiny openings called “stomata” present on the surface of leaves are responsible for the intake of carbon dioxide during the process of photosynthesis. Stomata regulate the exchange of gases, allowing carbon dioxide to enter the plant for use in photosynthesis, where it combines with water and sunlight to produce glucose and oxygen.