How does carbon dioxide enter the leaves of plants?

Carbon dioxide enters the leaves of plants primarily through small openings called stomata. These are specialized structures located on the leaf's surface, which can open and close to regulate gas exchange. When stomata open, carbon dioxide from the atmosphere can diffuse into the leaf, where it is then used in the process of photosynthesis to synthesize glucose and release oxygen as a byproduct.

The stomata play a crucial role in maintaining a balance between the uptake of carbon dioxide for photosynthesis and preventing excessive water loss through transpiration. The regulation of stomatal opening is influenced by various factors, including light intensity, humidity, and internal carbon dioxide levels in the leaf. This mechanism ensures that plants can efficiently gather the carbon dioxide needed for photosynthesis while also managing their water needs effectively.