environmental factors can influence natural selection because they can increase or decrease\no the number of…

Brief Explanations:

Natural selection acts on the genetic variation within a population. Environmental factors can affect the survival and reproduction of individuals in a population, which in turn can change the amount of genetic variation in the population. The number of chromosomes in an individual or population is a more stable genetic - related characteristic not directly influenced by environmental factors in the context of natural selection. Genetic variation within an individual is mainly determined by mutations and genetic recombination during meiosis, not directly by environmental factors in terms of natural - selection influence on the population level.

Answer:

the amount of genetic variation in a population.