How are oceans and rivers barriers to human trade, movement, and migration?

check all that apply.

a. they are a natural boundary.
b. they divide landmasses.
c. they can be hard to cross or navigate.
d. they might be hard to get to like the amazon.

Many areas surrounding the caspian sea contain important a. rare minerals b. forestry resources c. gold and silver mines d. oil and natural gas fields

In an effort to japan recover from the devastating effects of the 1929 depression, japanese military leaders in the 1930s formed an alliance with nazi germany negotiated more trade treaties with the soviet union closed its doors to western trade adopted a policy of imperialist expansion

Countries in this region are trying to achieve development. a. attainable c. sustainable b. suspendable d. intangible