a) The roots of a plant take up oxygen from the air trapped between the soil particles.

The roots use up the oxygen available to them from the air spaces present between the soil particles.

b) Diaphragm forms the floor of the chest cavity.

The movement of diaphragm along with the ribs helps in breathing.

c) Exchange of gases in the leaves take place with the help of stomata.

The stomata are the tiny pores (openings) present on the surface of leaves which help in transportation of Oxygen and Carbon dioxide in and out of the leaves.

d) Cockroaches breathe with the help of air tubes called trachea. Insects have a network of air tubes known as trachea which facilitates respiration.