Which of the following are responsible for surface currents a. the wind and density
b. win and he earth rotation
c. density and salinity
d. temperature and salinity

b. wind and the earth rotation

Explanation:

The surface oceanic water currents originates in the water due to the wind currents blowing over the surface of the water creating a specific pattern in the water and the other factor responsible is spinning motion of the earth. The surface oceanic currents forms a large circular pattern in the water that is called as gyre.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

a is the answer to this question

explanation: