Select all the correct answers.
giraffes with short necks lived in arid regions. over time, grasses disappeared, forcing giraffes to eat from trees. mutations in the genome led to
some giraffes inheriting the trait for long necks. over time, there were more giraffes with long necks in the region. what are the two reasons for
the change in the population of giraffes?

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.

explanation:

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.