Absorption. They absorb nutrience from dead/dying animals and/or plants.
Thermal pollution is when the water temperature goes from one extreme to another whether cold to hot or hot to cold, so I would say B.
"Stretching the neck enabled giraffes to reach higher, which gives them an advantage to survive, reproduce, and pass on this trait" is the one sentence among all the choices given in the question that best describes the claim. The correct option among all the options that are given in the question is the second option or option "B".