Question

read each example and identify it with one of the mechanisms that influence gene pools.
gene flow a zebra migrates to join a different herd of zebras.
genetic drift competition for sunlight leads to taller trees.
the dna of a snake changes to make its venom stronger.
mutation
gene flow
genetic drift
natural selection
a grassfire randomly sweeps through a population of buffalo and kills most of the

Explanation:

1. For "A zebra migrates to join a different herd of zebras": Gene flow is the transfer of genetic material between populations, and migration is a key part of gene flow. So this matches gene flow.
2. For "Competition for sunlight leads to taller trees": Natural selection (not genetic drift as originally selected, there was a mistake). Natural selection is when organisms with traits better suited to the environment (like taller trees competing for sunlight) are more likely to survive and reproduce. So this should be natural selection.
3. For "The DNA of a snake changes to make its venom stronger": Mutation is a change in the DNA sequence, so this is mutation.
4. For "A grassfire randomly sweeps through a population of buffalo and kills most of them": Genetic drift is random changes in allele frequencies due to chance events (like a random fire killing most of a population), so this is genetic drift.

Answer:

1. A zebra migrates to join a different herd of zebras: gene flow
2. Competition for sunlight leads to taller trees: natural selection
3. The DNA of a snake changes to make its venom stronger: mutation
4. A grassfire randomly sweeps through a population of buffalo and kills most of them: genetic drift