Which part of the plant is primarily responsible for photosynthesis?

The leaves are primarily responsible for photosynthesis in plants. This process occurs in specialized cells within the leaf that contain chloroplasts, which are organelles filled with chlorophyll. Chlorophyll is a green pigment that captures sunlight, which is essential for converting carbon dioxide and water into glucose and oxygen through photosynthesis.

The structure of leaves, often broad and flat, maximizes surface area for light absorption, making them efficient at engaging in this process. Additionally, leaves have tiny openings called stomata, which allow for the exchange of gases—taking in carbon dioxide and releasing oxygen.

In contrast, roots are mainly involved in water and nutrient absorption from the soil; stems provide support, transporting substances between roots and leaves; and flowers are primarily responsible for reproduction. Thus, while all parts of the plant have important functions, leaves are specifically adapted for photosynthesis, making them the correct answer in this context.