<span>Vesicles are used to transport items in many different circumstances, so I'm not quite sure how to answer your question. Vesicles are used when transporting to and from the golgi apparatus, also when transporting molecules to lysosomes. They are even used when undergoing exocytosis. Basically, they are used to carry items/molecules/wastes around within cells
as the altitude increases the air density decrease because of weaker gravity and these led to more distant of air molecule and the space between gas is increased
