Final answer:
During photosynthesis, sunlight is trapped in the leaves by stomata that are surrounded by guard cells.
Step-by-step explanation:
In plants, photosynthesis takes place primarily in the leaves, which consist of several layers of cells. The process of photosynthesis occurs in a middle layer called the mesophyll. The gas exchange of carbon dioxide and oxygen occurs through small, regulated openings called stomata, which are typically located on the underside of the leaf. These stomata are surrounded by specialized cells called guard cells that regulate the opening and closing of the stomata.