Which factor would increase population size? a. more competitors
b. unable to hide, defend, or migrate
c. ability to resist disease
d. inadequate food and resources
e. extreme temperatures

c

Explanation:

All the others would begin to kill off a population

the truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey.