Final answer:
A stretch of about 180 bases of DNA, coding for about 60 amino acids in a protein, which appears virtually intact in species as diverse as fruit flies and people is called a conserved sequence.
Step-by-step explanation:
The stretch of about 180 bases of DNA, coding for about 60 amino acids in a protein, which appears virtually intact in species as diverse as fruit flies and people, is called a conserved sequence. A conserved sequence refers to a region of DNA or protein that remains similar across different species, indicating a shared ancestry and important functional role. This conservation suggests that the sequence is critical for the protein's structure or function. For example, human cytochrome c is a conserved protein that contains a sequence of 37 amino acids that are found in the same position in the cytochrome c molecules of various organisms, including fruit flies and humans.