Which of the following factors influence the ocean currents?
1. Coriolis force
2. Gravity
3. Heating by solar energy
4. Wind
Select the answer using the code given below:

Ocean currents are influenced by two types of forces namely primary forces that initiate the movement of water and secondary forces that influence the currents to flow.

The primary forces that influence the currents are:
Heating by solar energy: It causes water to expand. Near the equator, the ocean water is about $8$ cm higher in level than in the middle latitudes. This causes a very slight gradient and water tends to flow down the slope.
Wind: Wind blowing on the surface of the ocean pushes the water to move. Friction between the wind and the water surface affects the movement of the water body in its course.
Gravity: Gravity tends to pull the water down the pile and create gradient variation.
Coriolis force: The Coriolis force intervenes and causes the water to move to the right in the northern hemisphere and to the left in the southern hemisphere.

Therefore, all the given factors influence the ocean currents.

Answer: 1, 2, 3 and 4