How has the geography of afghanistan made it difficult for invading armies to conquer? a. it is the second largest country, after russia. b. the terrain is mostly desert and mountains. c. mountains isolate the area, which has unified all afghans under one tribal affiliation. d. it is primarily bordered by water, which makes surprise attacks more difficult.

B. the terrain is mostly desert and mountains

Your answer is d. silli hope this ! : ) i left an explanation down below if you need it: a sill forms when hot magma squeezes between layers of rock to form a hardened sheet of rock. a sill is basically a tabular sheet intrusion between old layers of sedimentary rock, volcanic beds, or in the direction of foliation inherent in metamorphic rock. the word sill means a concordant intrusive sheet.