Question

scientists compile many pieces of evidence to infer evolutionary relationships. here is one such piece of evidence.
the gene hbb encodes a protein, beta - globin, that is involved in red blood cells ability to transport oxygen throughout an organisms body. this table shows the number of nucleotides in hbb that are identical between three different animals: mallard ducks, duck - billed platypuses, and panda bears.
which claim is best supported by this evidence?
of the three species, panda bears and mallard ducks are most closely related.
of the three species, mallard ducks and duck - billed platypuses are most closely related.
of the three species, duck - billed platypuses and panda bears are most closely related.

Explanation:

In evolutionary biology, the more identical nucleotides in a gene (like HBB here), the closer the evolutionary relationship. Duck - billed platypuses and panda bears have the highest number of identical nucleotides (376) among the pairs, indicating a closer evolutionary relationship compared to the other pairs.

Answer:

Of the three species, duck - billed platypuses and panda bears are most closely related.