Final answer:
The term for the approximate constant rate of sequence evolution observed in some macromolecules in some lineages is molecular clock. Molecular clocks are based on the assumption that mutations accumulate through time at a steady average rate for a given region of DNA.
Step-by-step explanation:
The term for the approximate constant rate of sequence evolution observed in some macromolecules in some lineages is molecular clock. A molecular clock is based on the assumption that mutations accumulate through time at a steady average rate for a given region of DNA. By comparing the DNA sequences of different species, scientists can estimate the time in geologic history when those species diverged from a common ancestor. Molecular clocks are commonly used in evolutionary biology to study the relationships and divergence times between species.