ABCTE Science Practice Exam

Transpiration primarily occurs through the leaves of a plant. This process involves the movement of water from the soil, through the plant, and eventually to the atmosphere as water vapor. Leaves are equipped with tiny openings called stomata, which are regulated by guard cells. These stomata allow for gas exchange, where not only is water vapor released, but carbon dioxide enters for photosynthesis as well.

As water evaporates from the leaf surface, it creates a negative pressure that helps draw more water up from the roots through the xylem, contributing to the plant's nutrient transport system. While roots, flowers, and stems play various roles in the life of a plant, it is the leaves that are primarily responsible for the process of transpiration.