Question

multiple choice question
why does natural selection occur?
because individuals must adapt to be able to survive in challenging environments.
because evolution strives to develop better traits.
because individuals move between populations and mix their genes.
because some individuals in a population possess heritable phenotypes that are more favorable than others.

Explanation:

Natural selection occurs when there is variation in heritable traits among individuals in a population. Individuals with more favorable heritable phenotypes are more likely to survive and reproduce, passing on those traits. Adaptation is a result of natural selection, not its cause. Evolution is not a goal - directed process to develop "better" traits. The movement of individuals between populations and gene - mixing is gene flow, not the cause of natural selection.

Answer:

Because some individuals in a population possess heritable phenotypes that are more favorable than others.