Question

Biologists estimate how long ago species separated from a common ancestor using a technique called

Answer 1

The answer is molecular clocks.

Molecular clocks use rates of mutation to measure evolutionary time. This technique is based on the fact that mutations add up at a fairly constant rate in the DNA of species that evolved from a common ancestor. The more mutations that happened in each lineage, the greater is the differences between these lineages and vice versa.

Answer 2

Your answer is molecular clocks.