Which of the following is NOT one of the mechanisms for evolution?

The mechanism of evolution encompasses several processes that contribute to the diversity and adaptation of organisms over time. Mutation, selection, and genetic drift are all established mechanisms recognized by evolutionary biology.

Mutation introduces genetic variability by altering DNA sequences, which can create new traits in a population. Selection, particularly natural selection, acts on these variations, favoring traits that enhance survival and reproduction. Genetic drift refers to random changes in allele frequencies within a population due to chance events, which can significantly impact genetic diversity, especially in small populations.

In contrast, the planarian response does not represent a mechanism of evolution. While planarians are a type of flatworm that may respond to environmental changes or stimuli, this response does not generate heritable changes in genetic material that would contribute to the evolutionary process. As such, it does not align with the recognized mechanisms that drive evolution.