Question

identify how scientists use vestigial structures to infer evolutionary relationships.
select the correct statement.
around the human ear are tiny, weak muscles. they no longer serve a purpose. this means that a common ancestor did not have those muscles to move their ears in response to sound. as humans evolved, the anatomical structure developed.
around the human ear are tiny, weak muscles. they serve a purpose. this means that a common ancestor once used those muscles to move their ears in response to sound. they must have had similar anatomical ears.
around the human ear are tiny, weak muscles. they allow us to hear sound. this means that a common ancestor also used those muscles to move their ears in response to sound.
around the human ear are tiny, weak muscles. they no longer serve a purpose. this means that a common ancestor once used those muscles to move their ears in response to sound.

Explanation:

Vestigial structures are remnants of organs or structures that had a function in an early ancestor. The tiny, weak muscles around the human ear no longer serve a purpose (they don't help us move our ears to detect sound like some animals can). But their presence suggests that a common ancestor once used those muscles for that purpose. The first option is wrong because it says the common ancestor didn't have those muscles (but vestigial structures imply the ancestor did). The second option is wrong as the muscles no longer serve a purpose. The third option is wrong because the muscles don't help us hear (they are vestigial, not functional for hearing).

Answer:

Around the human ear are tiny, weak muscles. They no longer serve a purpose. This means that a common ancestor once used those muscles to move their ears in response to sound.