Almost like clones in their similarity to one another, the penguin species’ homogeneity makes them especially vulnerable to disease.
A. the penguin species’ homogeneity makes them especially vulnerable to disease
"Almost like clones in their similarity" modifies penguins. It is the penguins that are similar in appearance not the "homogeneity"
B. the penguin species is especially vulnerable to disease because of its homogeneity
Penguin species can resemble to each other like clones, however note that in non-underlined part it says "their" whereas here we don't have any plural antecedent that "their" can refer to becuase penguin species is used as a singular noun "the penguin species is"
C. the homogeneity of the penguin species makes it especially vulnerable to disease
"Almost like clones in their similarity" modifies penguins. It is the penguins that are similar in appearance not the "homogeneity"
D. homogeneity makes members of the penguin species especially vulnerable to disease
"Almost like clones in their similarity" modifies penguins. It is the penguins that are similar in appearance not the "homogeneity"
E. members of the penguin species are especially vulnerable to disease because of their homogeneity.
Correct