Name the body structure concerned with the given functional activity :
Transports oxygen to the body cells

Explanation

**Step-by-Step Solution:**

1. **Understanding the Function**: The question asks for the body structure responsible for transporting oxygen to body cells. This involves identifying the system that facilitates gas exchange and transportation in the body.

2. **Identifying the Key Component**: The primary component responsible for transporting oxygen in the body is the blood. Blood circulates throughout the body and is essential for delivering oxygen to various cells and tissues.

3. **Role of Red Blood Cells**: Within the blood, red blood cells (RBCs) play a crucial role. They are specialized cells that carry oxygen from the lungs to the rest of the body.

...