If you were planning a long-distance sea voyage during the second half of the 15th Century to little-known destinations along unknown routes, what problems with the physical environment would you expect to have to deal with during the voyage

Storms and diseases.

Explanation:

Storms, food availability and diseases are the problems you expect to have to deal with during the voyage because the storms and ocean diseases occur to the people traveling in the voyage. Storm is the major problem facing by the people during travelling into the ocean because it is unexpected and they have to deal with it. Diseases also occur to the people during their travel and sometimes due to long journey people face food scarcity.

cuban communists pressured the soviet union to place missiles in cuba.

i'd assume india mainly because of how isolated japan was.   plus it is a whole china away.