AP BIOLOGY

Detailed explanation-1: -The transpiration rate is inversely proportional to the humidity in air. High humidity reduces the outward diffusion of water through the stomata. As a result, less water is lost, and lower transpiration rates are observed.

Detailed explanation-2: -As the relative humidity of the air surrounding the plant rises the transpiration rate decreases. It is easier for water to evaporate into dryer air than into more saturated air.

Detailed explanation-3: -At high atmospheric humidity, transpiration is low. This is because the rate of transpiration is directly proportional to the saturation deficit. It is dependent on the gradient of vapor pressure. Thus, the higher the humidity, the lower the rate of transpiration.