Which of the following is needed for natural selection to occur?

select one:
a. variation in characteristics
b. differences in fitness
c. heritability of characteristics
d. all of the above

Option D.

Variation in characteristics, differences in fitness and heritability of characteristics are needed for natural selection to occur.

Explanation:

Natural selection is a basic means of evolution in which organisms living in an environment adapt and change it's reproducing genetic constitution to better adapt in its environment. Four conditions are needed for natural selection to occur and these are variation in fitness, reproduction, heredity and variation in individual organism characteristics in a population.

organisms that are both used in toothpaste as well as cause malaria are protista and monera.