Final answer:
Spirometry is the test that helps assess the amount of air remaining in the lungs after a forced exhalation.
Step-by-step explanation:
The test that helps assess the amount of air remaining in the lungs at the end of a full, forced exhalation is called spirometry. Spirometry measures various lung volumes and capacities, such as the forced vital capacity (FVC) and the forced expiratory volume in one second (FEV1), which can indicate if there are any lung diseases or obstructions present. These measurements are important in diagnosing conditions like asthma, emphysema, and fibrosis.