Centrosomes are sites where protein dimers assemble into

Microtubules?

Explanation:

pretty sure its microtubules, centrosomes form during mitosis and function as the assembly area for microtubules that assist in the orientation of organelles within the newly forming cells, as well as the process of cell division.

answer; the correct answer is (beta)

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.