Question

Upwelling currents are caused by:

1.temperature differences between water masses
2.salinity differences between water masses
3.pressure differences between water masses
4.Ekman spiral

Answer 1

the answer would be 3!

upwelling currents are caused when the wind blows across the ocean surface , causing the water pressure to change between areas :)

Answer 2

Answer:

its the ekman spiral not pressure differences between water masses

Explanation:

Upwelling. Along some coasts, the Ekman spiral causes an upwelling of deeper water to replace the water that has moved offshore. The colder, deeper water is richer in nutrients. These upwelling areas contain some of the richest fishing grounds in the world.