Final answer:
Humans and chimpanzees share approximately 99% similarity in their DNA, indicating a very close evolutionary relationship and a recent common ancestor. Option 3.
Step-by-step explanation:
When single-stranded DNA from a human is mixed with single-stranded DNA from a chimpanzee, they exhibit a similarity of approximately 98%. This high percentage of similarity suggests that humans and chimpanzees share a recent common ancestor. Such genetic comparisons highlight the close evolutionary relationship between the two species and affirm our understanding of the process of evolution.
Moreover, this similarity extends to shared genetic codes that govern many biological functions. This high degree of genetic overlap between humans and chimpanzees indicates not only a surprisingly close relationship but also explains behavioral and protein function parallels seen across the two species.
Therefore, the correct answer to the student's question would be 3) 99% similarity, rounding to the nearest whole number, which reflects the high degree of commonality in the DNA sequences of humans and chimpanzees.