Final answer:
The principle that governs the relationship between tension and radius in the context of the alveoli is a)Law of Laplace.
Step-by-step explanation:
The principle that governs the relationship between tension and radius in the context of the alveoli is option a) Law of Laplace.
The Law of Laplace states that the tension in a spherical structure, such as an alveolus, is directly proportional to the radius and the pressure inside the structure. In the case of the alveoli, this means that as the radius of the alveolus decreases, the tension in the alveolar wall increases, which can lead to the collapse of the alveolus.