Which of the following most accurately reveals common ancestry among many different species of organisms?
Select an Answer
The amino acid sequence of their cytochrome C
Their ability to synthesize hemoglobin
The percentage of their body weight that is fat
The percentage of their body surface that is used in gas exchange
The mechanism of their mode of locomotion
To assess common ancestry or evolutionary relationships among organisms, differences or similarities in homologous structures are studied. Differences in homologous structures reflect the accumulation of mutations over time. The only choice listed that represents a comparison of a homologous structure is choice (A): Cytochrome C is a protein that can be studied and its amino acid sequences compared. The fewer differences in the amino acid sequence, the closer the relationship.