Question

question 9 of 20
how do these structures provide evidence for
common ancestry?
since the forearms of all three mammals are used
for the same purpose, the three species must
share a common ancestor that also used their
forearm for the same purpose.
because these structures are homologous, they
do not provide evidence for common ancestry.
only analogous structures would support
this claim.
these bones do not provide evidence for
common ancestry. it is just as likely that each
population individually evolved these structures.
while each forearm is used for a different
purpose, they contain modified versions of the
same bones.

Explanation:

Homologous structures (like the forearm bones of mammals shown) have similar anatomical patterns but different functions, indicating modification from a common ancestral structure—key evidence for common ancestry. The correct option describes this: shared bone structure despite different uses points to a common ancestor. Other options are incorrect (same purpose isn’t required, homologous structures do support common ancestry, independent evolution is less likely for identical bone patterns).

Answer:

While each forearm is used for a different purpose, they contain modified versions of the same bones.