Answer:
struggle for existence
survival for the fittest
Explanation:
In struggle for existence, members of the species die due to competition among individuals for food. The better suited giraffes with long necks could feed on the trees and survived.
In survival for the fittest, the well adapted long-necked giraffes were able to survive and reach the reproductive age to pass over their desirable traits to their offspring.
Answer:
Sexual selection in humans concerns the concept of sexual selection, introduced by Charles Darwin as an element of his theory of natural selection, as it affects humans. This has shaped our evolution for many years, but reasons why humans choose their mates are hardly understood.
Explanation:
