Answer:
The intrincate plumage of male birds of paradise has become increasingly elaborate throughout their evolution due to females mating preferentially with males that display the most impressive feathers. This is an example of NATURAL selection.
Explanation:
Darwin's Natural Selection theory states that some organisms tend to have more favorable traits between other organisms who belong to the same species. Upon this process and throughout adaptation, organisms pass on those treats to next generations. This gives place to reproduction and perpetuation of the species, avoiding extinction.