Which structure produces blood cells?

Blood cells are produced in the bone marrow of the body more specifically they become blood cells from first being stem cells which then divide until they reach a mature red blood cell stage. ( or other types of cells, stem cells are like the blank template for either red blood cells, white blood cells, or platelettes.)

Explanation:

answer; ////increased water pollution; ///////////////////////

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.