I believe it would be to calculate the amount of C-14 atoms left. scientists began to find out how long an object has been decaying, this has to do with half lifes etc. and how long a specific mineral/elements half life is. they use this to calculate how old it is (not an exact age but it's very accurate.)
Answer:
Phagocytic defense in the normal lung is shared principally by two kinds of cells - alveolar macrophages that reside on the air surface and roam the alveoli and PMNs that circulate in the intravascular space or are stored transiently in areas adjacent to the capillary-alveolar interface (marginated in capillaries)
Explanation:
mark brainliest pls
