Final answer:
The heart is medial to the lungs, situated within the mediastinum, and functions in both the pulmonary and systemic circulation circuits.
Step-by-step explanation:
The heart is medial to the lungs. Given the options, the most accurate is option number 4 - medial. The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum. The right side of the heart, which sends deoxygenated blood to the lungs in the pulmonary circuit, is deflected anteriorly, while the left side, sending oxygenated blood to the rest of the body as part of the systemic circuit, is deflected posteriorly.