A problem faced by the Mekong river is that large dams in are impeding its flow and interfering migration pattern of fish and their spawning. Another problem faced is reduced water flow affecting water traffic

The reason why i feel that the theory of plate tectonics is correct because scientists have found dinosaur bones of the same species in africa, asia, and in the americas. which means that they must have been together at one point in time. plate tectonics is also how the hawaiian islands were formed. as the plate hawaii is on was moving north west, magma would melt through the sea bottom and hardening. forming into the island chain. plate tectonics also explains the mariana trench. two plates were moving away from each other and made a giant crack in the ocean floor running 2,550 kilometers (1,500 miles)  long.

I'm pretty sure that the answer is c.

Because the fertile crescent had fertile soil that they could grow plants in 

The answer to your question would be c