What is the mechanism for proposed by darwin

its like this, "if i give a plant an unlimited amount of sunlight,then the plant will grow to its largest possible size."

hope it let me know if it does or doesn't =^-^=

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.