The oxygen transported in the blood is used by the body's cells for cellular respiration (aerobic respiration), a process that breaks down food molecules (like glucose) to generate the chemical energy (ATP) needed for all bodily functions.

A. removal of waste products: Oxygen is not directly used for the removal of waste products. Instead, waste products like carbon dioxide are generated from the process that uses oxygen and are then removed by the blood.

B. growth and development of cells: While oxygen is essential for the energy required for cell growth and development, it is the energy-releasing process itself (cellular respiration) that is the direct use of the oxygen, not the growth process in isolation.

C. formation of carboxyl haemoglobin: This option is incorrect because carboxyhemoglobin is formed when carbon monoxide (a poison) binds to hemoglobin, not oxygen. This binding prevents the normal transport of oxygen.