Answer
Transpiration is caused by the evaporation of water from the surface of plant leaves and other aerial parts. This evaporation is driven by environmental factors such as temperature, which increases the rate of water vapor loss, and wind, which can enhance the removal of water vapor from the leaf surface. Low humidity levels create a steep concentration gradient between the inside of the leaf and the surrounding air, promoting increased transpiration. Additionally, the process of transpiration is facilitated by the opening of stomata, which allows water vapor to escape into the atmosphere.