Why do gases exert pressure?

According to the kinetic molecular theory of gases, which of the following statements are correct?
$a$) The actual volume of the molecules is negligible in comparison to the empty space between them.
$b$) Collisions of gas molecules are inelastic.
$c$) At any particular time, different particles in the gas have the same speed and same kinetic energies.
$d$) Pressure is exerted by the gas as a result of the collision of the particles with the walls of the container.

If a gas is expanded at constant temperature,which of the following is true?

Which of the following represents the kinetic gas equation?

The transport of matter in the absence of bulk flow is known as:

Explain the kinetic energy,average translational kinetic energy,and root mean square speed of gas molecules.