Answer:
I am 99% the answer is A. Darwin did not discover Archaea, Evolution does NOT happen in a straight line, and variation is totally different than evolution.
Explanation:
Because it determines if it is isolated or not. This means if other substances can enter or not. This usually relies on the membrane with it´s pores. The pores help the membrane be selectively permeable in what it lets in and out.
There is only one measure of "evolutionary success": having more offspring. A "useful" trait gets conserved and propagated by the simple virtue of there being more next-generation individuals carrying it and particular genetic feature "encoding" it. That's all there is to it.
One can view this as genes "wishing" to create phenotypic features that would propagate them (as in "Selfish Gene"), or as competition between individuals, or groups, or populations. But those are all metaphors making it easier to understand the same underlying phenomenon: random change and environmental pressure which makes the carrier more or less successful at reproduction.
You will sometimes hear the term "evolutionary successful species" applied to one that spread out of its original niche, or "evolutionary successful adaptation" for one that spread quickly through population (like us or our lactase persistence mutation), but, again, that's the same thing.
Basically, there is a presentation of types of food and the amount of those foods over 50 years in this graph. This means the graph is showing amounts of certain foods over the time period. I'm guessing that basing off of the the previous text you're just noting a change in the breaks of birds based off of the diet available to them at certain times. The adaptations and natural selection will explain the changes because due to certain limited and available foods the diet of the birds change.
