The organ that pumps oxygen and nutrients to the tissues of the body is the heart.

Here's why:

* The heart is a powerful muscle: It acts as a pump, constantly contracting and relaxing to circulate blood throughout the body.

* Oxygenated blood: The heart receives oxygenated blood from the lungs and pumps it out to the rest of the body through the arteries.

* Nutrients: The heart also pumps blood carrying nutrients from the digestive system to the tissues.

While the lungs are responsible for taking in oxygen and the digestive system processes nutrients, it's the heart that actually delivers these essential substances to the body's cells.