In which of the following processes is chemical energy converted to mechanical energy?
question 10 options:

photosynthesis

a rock rolling down a hill

cellular respiration

muscle contraction

During a fierce storm a large number of tall trees on an island are uprooted by the wind and die. most of the trees on the island are now short trees and produce seeds that grow into short trees. what concept is shown in this example? question 5 options: natural selection artificial selection genetic engineering gene splicing