Which of the following is NOT a good example of naturalselection?
a. The increase in herbicide resistanceamong weeds on farms that use herbicides.
b. An increase in felineobesity over the last 2 generations due to gradually increasing fatcontent in cat food in the 90's and 2000's.
c. A decrease in allelicfrequency of brown rodents when an unusually snowy winter hits LasVegas, turning the desert white for months.
d. The increased percentageof drug-resistant microorganisms in patients being treated withdrugs.