Aside from low birthrates and high death rates what can cause a country's population to decline

Which statement explains what upwelling causes? a. upwelling causes tides to rise and fall. b. upwelling causes changes in the direction of currents. c. upwelling causes nutrients, minerals, and tiny organisms to rise. d. upwelling causes currents in the pacific ocean to change direction. i think the answer is c.

Why is terracing used in southeast asian agriculture?

In order from largest to smallest what are earths five main oceans