Both answers C and D are correct, however, answer D makes more sense.
<span>Notice a couple of things
different between (A) and (B). It was NOT the first time a biologist
proposed that species changed through time (so it's not B). But it
finally *solidified* that idea by giving "change through time"
(evolution) a MECHANISM. It gave a plausible explanation for WHY
species change over time, in a testable way that made sense and had
evidence to support it.
So it finally dismissed the idea that species are constant.
It also emphasized that the simple presence of *variation* within a population was a key reason for evolution.
While we're at it ... (C) is wrong because it's not *individuals* that
acclimate (adapt) to their environment, but the population (the species)
as a whole.
And (D) is wrong because it had nothing to do with economics or the monarchy.</span>
The correct answer is D, white blood cells.
We know that red blood cells deliver nutrients and are not apart of the immune system; platelets are responsible for coagulation, which has nothing to do with the immune system, and plasma is a substance that, again, has nothing to do with immunity. White blood cells are the only things that fight disease (antibodies are white blood cells)!
I hope I helped!
(By nothing I meant very little to none).
Answer: Heterotroph
Explanation: Good luck! :D
If you are referring to selection pressure, when the selection pressure decreases, there will be weaker forces of natural selection. The angler fishes without the favourable traits would not be that strongly selected against and vice versa. In some cases such as predation selection pressure, the population of angler fishes in the habitat may increase