Assuming the stomata are open to the same degree, the rate of transpiration should on a rainy day compared with a sunny day, because the relative size of the h2o concentration gradient from the inside to the outside of the leaf would ) increase: increaseb) decline: decreasec) increase: decreased) decline: increasee) remain the same: not change

decline: decrease

Explanation:

Transpiration is the loss of water from stomata by the process of evaporation. It occurs by the process of diffusion and is driven by the concentration gradient of water vapor. The higher the concentration gradient between air and leaf cells, the higher is the rate of diffusion of water.

On a sunny day, the rate of transpiration is higher since air is less humid and the concentration of water inside the leaf is higher. On the other hand, the air is more humid on a rainy day. The increased water vapor content of air reduces the concentration gradient between air and leaf cells. The reduced concentration gradient decreases the rate of transpiration.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: