Final answer:
The statement that membranes line body compartments opening to the external environment is True, with mucosal surfaces being an example. Mucosa lines body cavities exposed to the outside, distinguishing internal compartments.
Step-by-step explanation:
The statement "Membranes line body compartments that eventually open to the external environment" is True. Mucosal surfaces are the types of membranes that cover body cavities and internal passageways leading to the exterior, such as the digestive, respiratory, urinary, and reproductive tracts. In contrast, serous membranes are found in body cavities closed to the exterior. The tissue membranes serve as protective coverings and also separate internal body fluids from the external environment, ensuring that body compartments are distinct and internal systems operate without external disruption.
For example, mucosa lines various cavities in the body and covers the surface of internal organs that communicate with the exterior. To answer the multiple-choice question presented, option 'd. mucosa' correctly identifies the type of membrane that lines the body cavities exposed to the external environment.