What geographic challenges led to the use of island hopping?

your list doesn't mention any of them at all.

and what does "these" mean anyway ?

the correct answers are the following

a proxy war which functioned as a training field for wwii

republican democratic goverment

national side, leaded by the fascist general franco

the spanish civil war took place between 1936 and 1939 and was fought after a military coup undertaken on the 17th july 1936 by a group of generals that had seceeded from the spanish republican army, under the leadership of general franco, and who aimed to expel the democractically-elected republican goverment from power.

this war became a proxy war in which european powers tested their military equipment. on one side, urss and mexico supported the left-wing republican spanish goverment, while nazi germany and fascist italy supported the national fascist side.

franco managed to win the war in 1939, with the significant contribution of the foreign military support, and became the dictator of spain until his death in 1975.

explanation:

mark brainliest and have a great day!