Answer: chance.
- A chance
- B natural selection only
- C only mutation
- D only migration
Correct answer: A. chance
Explanation: Genetic drift is a random change in allele frequencies, strongest in small populations.
A simple phylogenetic tree: a common ancestor branches into several descendant lineages over time, with each branch point marking a speciation event.
Concept context
Origin of life, Darwin's theory, natural selection, speciation, and evidence for evolution.