How long should you hold a stretch?

Which of the following are considered general purposes of performing pulmonary function tests (pfts)? 1. the functional status of the lungs 2. the diffusion characteristics of the alveolar-capillary membrane 3. how much and how fast gas can be moved into and out of the lungs 4. the specific diagnosis of pulmonary disease

Which is the lipid molecule that controls what types of molecules can pass though?

How can someone meet the need to belong in a healthy way?