Which factors remained constant in each trial? Check all that apply.
A. the total number of people
B. the series of people who exchanged liquids with each other
C. the number of people who were infected at the end of the lab
D. the number of exchanges
E. the number of individuals who were initially infected

A, B, D, E

Explanation:

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.