Which are two ways that igneous rock are classified

The first amino acid of a new polypeptide chain is

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of

Rarefaction is used for which of the following? a. creating a representative sample b. studying how disease impacts populations c. rediscovering species thought to be instinct d. determining which sea creatures live in an area