How does density cause deep water currents to form?

Dense water sinks below less dense water. This is the principle that drives the deep ocean currents that circulate around the world. A combination of high salinity and low temperature near the surface makes seawater dense enough to sink into the deep ocean and flow along the bottom of the basins.

Explanation:

a and b because with the other three, they simplify to something else.

for e2020. the answer would be some directions from the mountain range so we can find mt. whitney. to locate which direction is north, you should use a   compass. this would not only find mt. whitney, but also becuase of this long paragraph you would get points because it's not like anyone actually reads your work becuase once they read the first sentence it sounds dumb enough to not read becuase i'm not good at answering this but the answer is compass for your benefit.

for e2020 ; -;