Peristalsis is the process of contractions that move food through the intestines.
B. energy transferred from the sun to plants and then to a series of living things.
Adaptation
The idea of "survival of the fittest" applies here. The phenotypes of the organisms the survive are the ones that get passed on to future generations while those of organisms who die off do not pass their phenotypes. Only the phenotypes that are better suited to the environment get passed on and, therefore, occurs more frequently in their populations.