Question

question 2 of 10
how do vestigial structures serve as evidence to support the theory of
evolution through natural selection?
a. similar structures in different species that have different functions
are the result of organisms adapting to similar environments.
b. structures that are used infrequently become smaller and are not
passed on to offspring.
c. structures that have little or no function exist because an ancestor
once had a functional version.
d. structures in different species that have similar functions show
that all organisms have a common ancestor.
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Explanation:

Vestigial structures are remnants of organs or structures that had a function in an early ancestor. For example, the human appendix is thought to be a vestigial structure. In some herbivorous ancestors, the appendix was larger and played a role in digesting cellulose - rich plant material. As human diet and digestive processes evolved, the appendix lost its major digestive function but still remains in the body. This shows that over time, through the process of evolution (including natural selection where traits that are no longer as useful may be retained in a reduced form), such structures exist as evidence of evolutionary history. Option A refers more to convergent evolution (not vestigial structures). Option B is incorrect as vestigial structures are passed on (just in a reduced form). Option D is about homologous structures with similar functions (not vestigial which have little or no function now) and the statement in D is also an over - generalization as not all organisms with similar - function structures have a common ancestor in that simple way.

Answer:

C. Structures that have little or no function exist because an ancestor once had a functional version.