The similarities of gene sequences and metabolic pathways across the three domains of life are evidence for:
A) evolution.
B) a common ancestor.
C) cross-species genetic transfer.
D) both evolution and a common ancestor.
E) both a common ancestor and cross-species genetic transfer.

Question

Quizplus · Accepted Answer

The similarities of gene sequences and metabolic pathways across the three domains of life suggest that all life on Earth shares a common ancestor, which would have had those sequences and pathways. As evolution occurs through modification of existing genes and pathways, these shared features also provide evidence for evolution. Therefore, the best choice is D, both evolution and a common ancestor. There is no direct evidence to support cross-species genetic transfer as an explanation for these similarities.

The Similarities of Gene Sequences and Metabolic Pathways Across the Three