Which line of defense includes active immunity 1st 2nd 3rd 4th

Second line

Explanation:

I did a test with this answer. Mark as brainliest if this is correct sorry if I'm too late :D.

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.

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.