Which of the following is not an example of the force of gravity?

Explain why the walls of a dam are thicker near the bottom than at the top.

Which of the following is not an example of muscular force?

When we press the bulb of a dropper with its nozzle kept in water air in the dropper is seen to escape in the form of bubbles. Once we release the pressure on the bulb, water gets filled in the dropper. The rise of water in the dropper is due to :

A rectangular wooden block has length, breadth and height of 50 cm, 25 cm and10 cm, respectively. This wooden block is kept on ground in three different ways, turn by turn. Which of the following is the correct statement about the pressure exerted by this block on the ground?