Answer:
1. **Circulatory System:** Responsible for transporting blood, nutrients, and oxygen throughout the body, consisting of the heart, blood vessels, and blood.
2. **Respiratory System:** Involved in the exchange of oxygen and carbon dioxide, includes the lungs and respiratory passages like the trachea and bronchi.
3. **Nervous System:** Coordinates and controls body activities through the brain, spinal cord, and nerves, allowing communication between different parts of the body.
