Diabatic processes occur when:

a. rising air expands and cools without gaining or losing energy.

b. are the primary force behind cloud formation.

c. do not always conform to the Second Law of Thermodynamics.

d. add or remove energy from a system.

The correct answer is d. add or remove energy from a system.

Explanation:

A diabatic process can be defined as one where a system exchanges energy with the surroundings resulting in a thermodynamic change of the system's state.

Diabatic processes can be grouped into five categories viz

1. Terrestrial radiation.

2. Solar radiation

3. latent heat flux

4. sensible heat flux

5. friction process

In the same vein, an adiabatic process is one in which there is zero heat, mass or momentum transfer across the bounary of the thermodynamic system