Question

the main, or central, idea of the passage is chimpanzees and humans have surprisingly similar dna. how does the detail in bold develop the main idea? humans and chimpanzees descended from a common ancestor, a gorilla - like creature that lived millions of years ago. even in light of this fact, it is astonishing to learn just how similar humans and chimpanzees are when it comes to their genes. in fact, the two species dna differs by only 1.2 percent. a laboratory comparison of chimp and human chromosomes—strands of dna each containing approximately 1,100 genes—reveals a strikingly similar pattern. perhaps surprisingly, chimpanzees are genetically closer to humans than to gorillas. admittedly, the apparently small 1.2 percent variation between chimps and humans still corresponds to forty million differences in dna base pairs. still, the tremendous genetic similarity indicates that the chimpanzee (along with the bonobo, another ape) is our closest living relative. it specifies the extent of the genetic similarity. it offers an alternative interpretation of dna research. it suggests the initial reason why scientists pursued research on dna similarity.

Explanation:

The bold - faced detail about the 1.2 percent DNA difference and forty - million base - pair differences quantifies how similar and different chimp and human DNA is, thus specifying the extent of genetic similarity.

Answer:

It specifies the extent of the genetic similarity.