Hey ardz24,

We have a modifier here - we can tell because the first part of the sentence is set off from the rest of the sentence and includes a pronoun ("their") that doesn't refer to anything ... yet. Modifiers refer to the noun that is closest to them.

Here our modifier is "Almost like clones in their similarity to one another". So what does "their" refer to? What are so similar that they are "like clones"? Based on the sentence, it would make the most sense for "their" to refer to "cheetahs" - cheetahs are so similar (or "homogenous") that they are vulnerable to disease. So we want to find a sentence that puts "cheetahs" closest to our modifier.

We can rule out A, C, and D because "homogeneity" is not at all what we want - homogeneity is almost like clones? Doesn't make sense.

B is a little trickier. Here, "the cheetah species" is our subject. However, "The cheetah species is almost like clones in their similarity to one another" doesn't actually make much sense. We see that "species" is singular (it can be plural, but here it's followed by singular verb "is"), but the pronoun in the modifier, "their", is plural. It also isn't clear what "one another" would be? The species is like clones with other species of animal? Other species of cheetah? So we can rule out B.

This leaves us with E, which tells us that members of the cheetah species are almost like clones.