Answer:
Adapt
Step-by-step explanation:
According to Charles Darwin, there is a constant struggle for species survival, in which individuals best adapted to their environment (not necessarily the strongest) are able to survive and continue the species.
Example: In a snowy environment, white fur mammals are more difficult to find by their predators than black fur mammals.
Therefore, these will have a higher survival rate, and consequently a higher reproduction rate. Then, over time, the population of white fur mammals will outnumber the black fur population.