NEET BIOLOGY

Detailed explanation-1: -Chromosome number is not a factor that influences natural selection. The other three choices represent factors that drive the process of natural selection. Random mutations in DNA provide genetic variation in a population of species and allow for natural selection to occur.

Detailed explanation-2: -There are four principles at work in evolution-variation, inheritance, selection and time. These are considered the components of the evolutionary mechanism of natural selection.

Detailed explanation-3: -Natural selection occurs only if there is both (1) variation in the genetic information between organisms in a population and (2) variation in the expression of that genetic information-that is, trait variation-that leads to differences in performance among individuals.

Detailed explanation-4: -The correct answer is: Bacterial populations in hospitals acquire resistance to antibiotics used to treat illness.