Which of the following describes a phenomenon that occurs when we observe plants that wilt?
a. the xylem releases all its water.
b. the stomata close, cutting off transpiration and gas exchange.
c. the roots begin to rot, causing them to no longer uptake water.
d. the plant begins absorbing oxygen and releasing carbon dioxide into the atmosphere

B. Stomata closes, cutting off transpiration.

Explanation:

On a hot, dry day (or after several days with no rain or watering), transpiration causes more water to be lost than is coming in, and the water balance within the plant can get thrown off. The dehydrated collapsing cells in the leaves and stems can no longer remain erect, and the plant begins to wilt.