Creatures that are poorly suited to the environment do not generally weaken the entire population because

A. The population protects its own

B. They often die before they can reproduce

C. All populations have some weak members

D. Populations have more weak members than strong ones

B

Explanation:

If a creature doesn't suit to its surrounding enviroment，it will die before it can reproduce. Survival of the fittest

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.