Which of these describes the factor that has the greatest effect on surface currents and explains why?

a: the wind's energy, because the wind drives the surface currents

b: the moon's gravity, because the tides control the surface currents

c: the seafloor features, because the surrounding seafloor determines the surface currents

d: the differences in salinity, because water moving from larger to smaller levels of salinity causes surface currents

Water is siphoned from a large tank and discharges into the atmosphere through a 50-mm diameter tube. the end of the tube is b = 2.6 m below the tank bottom which is a = 6.7 m deep, and viscous effects are negligible. determine the maximum height h over which the water can be siphoned without cavitation occurring. atmospheric pressure is 101.4 kpa, and the water vapor pressure is 1.79 kpa (absolute). report your answer in meters to two decimal places.