Question

question 9 of 10
why are vestigial structures not removed by natural selection?
a. they do not harm the organism.
b. vestigial structures are genetic traits.
c. only unimportant structures can be removed.
d. they are helpful to the organism.

Explanation:

Natural selection removes traits that are harmful. Vestigial structures are remnants of organs or structures that had a function in an early ancestor. Since they do not harm the organism, there is no selective pressure to remove them. For example, the human appendix. It is a vestigial structure. It does not cause significant harm (in most cases), so it remains in the human body. Option B is incorrect because vestigial structures are not necessarily genetic traits in a way that explains why they aren't removed. Option C is wrong as the statement “Only unimportant structures can be removed” is not a valid biological principle. Option D is incorrect because vestigial structures are not helpful (by definition, they have lost their original function).

Answer:

A. They do not harm the organism.