Final answer:
The true statement based on a graph showing biochemical differences is that monkeys share more amino acid sequences with humans than with fish. This is evidenced by the high degree of similarity found in the protein sequence of cytochrome c in monkeys and humans. The correct option is A) Monkeys share more amino acid sequences with humans than they share with fish.
Step-by-step explanation:
The correct statement based on the graph showing biochemical differences is A) monkeys share more amino acid sequences with humans than they do with fish. Through the study of cytochrome c, we understand that humans share a closer common ancestor with primates like chimpanzees and rhesus monkeys than with other organisms, such as yeast or fish. The human and chimpanzee cytochrome c protein sequences are identical, and the human and rhesus monkey sequences differ by only one amino acid. On the other hand, the human-to-yeast comparison shows a difference in 44 amino acids.
Options B, C, and D are incorrect because they either illustrate a misunderstanding of evolutionary relationships or misstate the molecular evidence. For instance, moths are unlikely to be more closely related to candida than turtles are to pigs because they are in completely different domains of life.
Fish do share amino acid sequences with humans, as indicated by the shared 37 amino acid positions in cytochrome c. Lastly, the cytochrome c of ducks would not be unrelated to that of humans because all organisms that have had their cytochrome c sequenced show a certain degree of similarity due to common ancestry.