Final answer:
If two animals have identical sequences of amino acids in a protein, it suggests that they likely share a recent ancestor. These molecular similarities provide insights into evolutionary relationships, and are considered strong evidence for the animals being related. The correct option is D.
Step-by-step explanation:
The fact that two animals have an identical sequence of amino acids in a protein indicates that these animals likely share a recent ancestor. In evolutionary biology, such similarities are due to common descent. If a protein sequence is conserved between two species, it means there was little to no changes in that protein since the time of their last common ancestor. This is considered strong evidence for the animals being related.
It does not necessarily mean that they are in the same genus or eat the same types of food, and it doesn't tell us anything about their exposure to substances that cause mutation.
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