When the wind blows, this spins.

well, since there is no answer choices, i will give an answer on how it works : )

the two objects are placed together. energy will always be transferred from the hotter object to the cooler object until they are equal. hope this is close to one of the answer choices : )

lichens that colonize bare rock secrete acids that break down the rock and start the soil-production process. so they expose rocks