What happens during the process of transpiration?

Transpiration is a vital process in plants where water vapor escapes from the plant into the atmosphere primarily through small openings on the leaves called stomata. This process serves several important functions. Firstly, it aids in the regulation of temperature within the plant by providing a cooling effect, especially on hot days. Secondly, as water vapor exits through the stomata, it creates a negative pressure in the plant's vascular system, facilitating the upward movement of water and nutrients from the roots to the leaves through capillary action.

The stomata open primarily to allow gas exchange, including the intake of carbon dioxide for photosynthesis, but their primary role in transpiration is to release water vapor. This process is essential in maintaining the plant’s hydration and contributes significantly to the water cycle by returning water vapor to the atmosphere. Thus, the correct understanding of transpiration revolves around the movement of water vapor out of the stomata, accurately represented by the chosen answer.