In his theory of natural selection, Darwin incorporated the premise that available resources were not sufficient for all members of a population to survive. Darwin adopted these ideas of competition and survival from

Malthus.

Explanation:

In his theory of natural selection, Darwin incorporated the premise that available resources were not sufficient for all members of a population to survive. Darwin adopted these ideas of competition and survival from  Malthus. Malthus theory of population growth states that if population growth is left unchecked, it will exceed available resources. Drawing from this premise, Darwin in his theory of natural selection asserts that due to lack or resources or unfavourable conditions, organisms who develop adaptive capacities will survive and pass those adaptive/coping mechanisms to their offspring, while those organisms who cannot adapt will die out.

bujías y una hora antes y no me parece muy difícil

roosevelt believed that in light of the country's recent military successes, it was unnecessary to use force to achieve foreign policy goals, so long as the military could threaten force. this belief, and his strategy of “speaking softly and carrying a big stick,” shaped much of roosevelt's foreign policy.