What mechanism of evolution occurs when a new version of a trait arrises in a population?Group of answer choicesgenetic driftnonrandom matingmutationgene flow

The mechanism of evolution that occurs when a new version of a trait arises in a population is mutation.

Here's a step-by-step explanation:

1. Mutation is a change in the DNA sequence of a gene. This can happen due to errors in DNA replication or repair, or due to exposure to certain chemicals or radiation.

2. When a mutation occurs, it creates a new version of a trait. This new version can then be passed on to future generations.

3. If this new trait is beneficial, it can increase in frequency in the population over time through natural selection. This is how evolution occurs.

4. The other options - genetic drift, nonrandom mating, and gene flow - are also mechanisms of evolution, but they do not directly cause new traits to arise. Instead, they affect how traits are distributed or change in frequency in a population.