The keystone species is the one at the bottom of the pyramid, if we look at it like a pyramid. If the grass dies, then the deer cannot get food and die, and the predator cannot eat and dies, and the whole ecosystem can fall apart.
A) both have strong scientific support.
Answer:
Greenhouse gases absorb this energy, thereby allowing less heat to escape back to space, and 'trapping' it in the lower atmosphere. Many greenhouse gases occur naturally in the atmosphere, such as carbon dioxide, methane, water vapor, and nitrous oxide, while others are synthetic.
I believe the answer would be B I think sorry in advance if im incorrect
