As a result of dna testing, scientists learned the black death was

the pneumonic plague, not the bubonic plague.

both the pneumonic plague and the bubonic plague.

caused by fleas on cats and dogs.

caused by fleas on rats and vermin.

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.

d: their own individual powers within the new goverment

on april 6, 1917, the u.s. joined its allies--britain, france, and russia--to fight in world war i. under the command of major general john j. pershing, more than 2 million u.s. soldiers fought on battlefields in france.