Question

what is the best description of fitness as darwin referred to it?
the amount of exercise an individual gets
the speed at which an organism can travel
the relative ability to adapt and survive in an environment
rewatch

Explanation:

Darwin's concept of "fitness" (biological fitness) relates to an organism's ability to survive and reproduce in its environment, which ties to adapting to environmental pressures. The first option is about physical exercise (not Darwin's meaning), the second about speed (not core to fitness). The third option matches the evolutionary definition of fitness as the ability to adapt and survive (and reproduce) in an environment.

Answer:

the relative ability to adapt and survive in an environment