1. Succession is best defined at as a series of changes that occur in an ecosystem over time: a) random
b) predictable
c) rapid
d) beneficial

Am not sure if this helps but this is what I found.

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.

bc blah

explanation:

bc blah