The process by which plants lose water vapor is called transpiration. During transpiration, water absorbed by roots is transported through the plant to small pores on the leaves known as stomata. When these stomata open for gas exchange—allowing carbon dioxide in and oxygen out—water vapor escapes into the atmosphere. Transpiration is essential for plant health, helping to regulate temperature and facilitate the movement of nutrients through the plant. It also plays a crucial role in the water cycle, contributing to moisture in the air and influencing weather patterns. Conversely, excessive transpiration can lead to water stress in plants.