Which substance, needed by the body cells, enters the body through the lungs? Hemoglobin D Carbon dioxide Nitrogen D Oxygen

The correct answer is D) Oxygen.

Oxygen is the substance that is needed by the body cells and enters the body through the lungs. When we breathe in, oxygen-rich air enters the lungs, where it is absorbed into the bloodstream. The oxygen is then transported to the body cells, where it is used for cellular respiration, a process that produces energy for the cells to function.