Question

species a, b, and c all make actin, a protein that helps muscles contract. the amino acid sequences of actin protein are 90% identical between a and b, but only 70% identical between a and c.
a. based on the evidence above, choose the statement that is most likely to be correct.
b. choose the tree - diagram that shows the correct relationship.
a shares a more recent common ancestor with c than with b; a shares a more recent common ancestor with b than with c

Explanation:

The more similar the amino - acid sequences of a protein in different species, the more recently they diverged from a common ancestor. Since the amino - acid sequences of actin protein are 90% identical between A and B and only 70% identical between A and C, A shares a more recent common ancestor with B than with C. In a phylogenetic tree, species that share a more recent common ancestor are grouped more closely together.

Answer:

a. A shares a more recent common ancestor with B than with C
b. Tree 2 (where A and B are grouped more closely together)