Bernoulli's equation is applicable to points

Bernoulli's equation is based upon:

The horizontal flow of fluid depends upon

A tank is filled with water up to height $H$. Water is allowed to come out of a hole $P$ in one of the walls at a depth $D$ below the surface of water. Express the horizontal distance $x$ in terms of $H$ and $D$

An incompressible liquid flows through a horizontal tube as shown in the figure. Then the velocity '$v$ of the fluid is

For a fluid which is flowing steadily, the level in the vertical tubes is best represented by