transportation is what is making it so difficult
Rivers are divided by watershed boundaries, lines that follow the hirght og the loand and the water drians off in the opposite directions. In nature it is virtually impossible to see where oneregion of vegetation starts and ends. Natural vegetation regions gradually change through transition zones.
Answer: D. Samples of ocean water tested off the coast of South America contained the same salt content as oceans near Africa.
Explanation:
idk how to answer this my guess is B. or C.