<span>Ethology is a branch of zoology concerned with the study of animal behavior. Ethologists take a comparative approach, studying behaviors ranging from kinship, cooperation, and parental investment, to conflict, sexual selection, and aggression across a variety of species.</span>
Answer:
Savanna do not exist in the united states because there are no true tropic climates.
Two things that INCREASE population, would be an increase in leisure space. Another is if the area is sustainable for life. Two things that would DECREASE population, would be a scarcity of any required resources. A decrease in space, and not a sustainable area.