What type of process is respiration?

$A$ process is occurring throughout the day in an organism '$X$'. Cells are participating in this process. During this process, $ATP, CO_2,$ and water are evolved. It is not a light-dependent process. Is it a catabolic or an anabolic process?

If a starving plant is provided with glucose,the rate of respiration would

Respiration occurs in .........

The minimum rate of respiration is found in ......... .

When a substrate is being metabolized,why does not all the energy that is produced get released in one step? It is released in multiple steps. What is the advantage of step-wise release?