In 1986, a nuclear power accident in Chernobyl, USSR (now Ukraine), led to high radiation levels for miles surrounding the plant. The high levels of radiation caused elevated mutation rates in surviving organisms, and evolutionary biologists have been studying rodent populations in the Chernobyl area ever since. Based on your understanding of evolutionary mechanisms, which of the following most likely occured in the rodent populations following the accident?

a.) Mutations caused major changes in rodent physiology over time.

b.) Mutation caused genetic drift and decreased fitness.

c.) Mutation caused the fixation of new alleles.

Radiation leads to mutations that causes genetic drift and decrease fitness.

Explanation:

Radiation is responsible for changing or altering the DNA sequence within a cell.

Radiation either causes mutation or it leads to cell death.

Most of the ionizing radiation causes mutation within the  deep inside of our cells which eventually leads genetic drift which means change in the frequency of the allele in a population over time.

Beneficial mutation confer advantage to the organism. But in this case, the mutation is not beneficial and decreases the fitness of the rodent organisms.  

the unequal cytoplasmic division that  results  in  one egg  and three polar bodies ensures that a fertilized  egg has  ample nutrients  forits journey  to  the uterus.