The correct answer is a) peahens choose to mate with peacocks that have the most beautiful tails. Sexual selection is a specific form of natural selection where certain traits increase an individual’s chances of mating and reproduction based on preferences displayed by the opposite sex.
In this example, peahens (female peafowl) select peacocks (male peafowl) to mate with based on the appearance of their tails. Peacocks with larger and more colorful tails are more likely to attract female mates, as these traits may signal genetic quality or fitness. This behavior exemplifies sexual selection because the mating choices of the females directly influence the evolution of male traits.
Options b, c, and d do not represent sexual selection: option b relates to bacterial evolution and fitness, option c refers to genetic processes unrelated to mate selection, and option d mentions cheetahs without connecting to mate choice. Thus, option a is the only correct example of sexual selection.