In the last few centuries, the number of species becoming extinct on earth has
a. decreased dramatically
b. decreased slightly
c. increased slightly
d. increased dramatically

The correct answer is d.  increased dramatically

Explanation:

In the last century, nearly 500 species got extinct mainly because of the destruction of their natural habitat caused by human beings.  

Humans cut down the forest for making land for agriculture and homes. According to World Wildlife Fund every year earth loss 18.7 million acres forest due to human influence which is the home of thousands of animal and plant species.

The natural rate of extinction is 9 species but in the last century, almost 500 species got extinct which shows that In the last few centuries, the number of species becoming extinct on earth has increased dramatically.

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

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).