You're going to have to give me the choices.
I'm pretty sketchy on that subject.
It’s more dense than air and less dense than liquid!
Answer: The energy to move the fluid is provided by the pressure on the fluid surface.
Explanation: The frictional losses in the suction pipework and rises in the suction pipework system will reduce the fluid pressure at the pump inlet. If the pump inlet connection is removed the fluid will not flow out of the suction pipework. Hope this helps! :)