The meaning is, "the taking in of matter by a living cell by invagination of its membrane to form a vacuole."
Alveolar walls are thin to enable the quick passage of oxygen in and out of the lungs. The lungs works hand-in-hand with the heart and also is responsible in converting blood that's de-oxygenated into an oxygenated blood that is usable by the organ systems of the body. The alveolar walls are also designed to have thin membranes so that it can expand and constrict quickly allowing us to breather properly.
Builds protein is the correct answer
Due to the reduction in large industrial emmissions such as fertilizers into water zones.
