Explain how trait variations give mating advantages Practice Test

Many species of frogs attract their mate with vocal calls and noises. Which variation in vocal calls would best help a frog attract a mate?

For many species of male ducks, the birds that have the most ornate and colorful feathers are selected as a mate. The female birds are more muted in color. The females must sit on the nests to incubate their eggs, and the brown colors help them to blend in from predators. Also, male ducks are larger than the female ducks.

Why would the female look for the largest and most colorful male duck to be her mate?