When working with humans or animals, the requires extensive proof that no physical or mental harm will occur to the subjects in the study?

Ifound this on google “here are some features of the alveoli that allow this: they give the lungs a really big surface area. they have moist, thin walls (just one cell thick) they have a lot of tiny blood vessels called capillaries.for more information go to the website below › bitesize › guidesi hope this you for what your looking for. can you plz mark me brainliest?

1. protection 2. homeostasis 3. storage4.blood formation5.bone marrow 6.movement