Question

Why is DNA a useful evolutionary clock?

DNA mutations cause organisms to diverge evolutionarily from one another.
DNA is the only substance in an organism that never changes.
DNA contains no carbon, so it is not affected by radioactive decay.
DNA decays steadily over time once an organism dies.

Answer 1

The answer is DNA mutations causing divergence in evolution.

Mutation is the engine of evolution in that it generates the genetic variation on which the evolutionary process depends. To understand the evolutionary process we must therefore characterize the rates and patterns of mutation.

Mutations are also part of natural selection as certain mutations causes living things to die off and be replaced with one that is more suitable for its living environment.