Explain why :(a) To keep a piece of paper horizontal, you should blow over, not under it

Explain why :
(a) To keep a piece of paper horizontal, you should blow over, not under it
(b) When we try to close a water tap with our Angers, fast jets of water gush through the openings between our fingers.
© The size of the needle of a syringe controls flow rate better than the thumb pressure exerted by a doctor while administering an injection.
(d) A fluid flowing out of a small hole in a vessel results in a backward thrust on the vessel.
(e) A spinning cricket ball in air does riot follow a parabolic trajectory.