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.
Explanation:
Igneous rock is formed through the cooling and solidification of magma or lava.
<u><em>Chromosomes</em></u> asserts that our genes set the boundaries within which we can operate
<span>True. A valid hypothesis must be testable and able to be verified or disputed empirically, because otherwise it is not a scientific hypothesis. A hypothesis that is not readily testable (for example, about a made up or fictional event) are not good hypotheses.</span>