What is the last step involved in respiration?

Whales are air-breathers but can live underwater for a long time because they possess:

In most of the thin-leaf mesophytes,the leaf stomata open during the day and close during the night. This pattern is known as:

For completion of the respiration process,write the given steps in sequential manner.
$(a)$ Diffusion of gases ($O_2$ and $CO_2$) across alveolar membrane.
$(b)$ Transport of gases by blood.
$(c)$ Utilisation of $O_2$ by the cells for catabolic reactions and resultant release of $CO_2$.
$(d)$ Pulmonary ventilation by which atmospheric air is drawn in and $CO_2$ rich alveolar air is released out.
$(e)$ Diffusion of $O_2$ and $CO_2$ between blood and tissues.

During rest,the metabolic needs of the body are at their minimum. Which of the following is indicative of this situation?

Which of the following statement$(s)$ is/are correct?
$(a)$ High concentration of carbonic anhydrase in RBCs.
$(b)$ High concentration of carbonic anhydrase in blood plasma.
$(c)$ Every $100 \ ml$ of deoxygenated blood delivers approximately $4 \ ml$ of $CO_2$ to the alveoli.
$(d)$ $20-25\%$ of $CO_2$ is carried by hemoglobin as oxyhemoglobin.