Question

read each example and decide whether each would increase or decrease the genetic variation in the gene pool of that population
a zebra migrates to join a different herd of zebras
competition for sunlight leads to taller trees
the dna of a snake changes to make its venom stronger
a grassfire randomly sweeps through a population of buffalo and kills most of the animals

Explanation:

Answer:

A zebra migrates to join a different herd of zebras: Increase
Competition for sunlight leads to taller trees: Decrease
The DNA of a snake changes to make its venom stronger: Increase
A grassfire randomly sweeps through a population of buffalo and kills most of the animals: Decrease