(a) A gas fills completely the vessel in which it is kept.
(b) A gas exerts pressure on the
walls of the container.
(c) A wooden table should be
called a solid.
(d) We can easily move our hand
in air but to do the same
through a solid block of wood
we need a karate expert.

a)The force of attraction between particles of gas is negligible. Because of this, particles of gas move in all directions. Thus, a gas fills the vessel completely in which it is kept.

b)Because of negligible force of attraction between particles of gas, the particles of gas have the highest kinetic energy. These properties enable the particles of gas to move in all directions and hit the walls of container from all sides. Because of this a gas exerts pressure on the walls of the container in which it is kept.

c): A wooden table has fixed shape and fixed volume, which are the main characteristics of solid. Thus a wooden table should be called a solid.