When the immune system detects a pathogen in the body, the cells respond

trachea, alveoli, lung capillaries, arteries

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds

b) the inside picture would look at a very high temperature in a very low ph

a chain link fence because there so tiny even my albino donkey can't get out