What "hidden" passenger came on board European ships and led to a devastating epidemic amongst the Native Americans?

By the late 1930s, how were u.s. officials beginning to view japanese policies of expansion? a. they attempted to join forces with japan so as to increase u.s. territory. b. they warned them to stop expansionist actions or face potential u.s. intervention. c. they sent representatives to japan to work out territorial rights in a diplomatic fashion. d. they became fearful of their military power

Brainliesttt !me : ) -what is invisible warfare?

After the success of the sputnik launch, the united states feared that they would never be able to launch their own satellite, the ussr had used technology developed by the united states, the soviets had superior nuclear capabilities, that any future us satellites would not be as successful.