The quantity, '1 mole of atoms of an element', refers to the mass of?

In an exothermic reaction the bonding energy of the product is: less than the reactants same as the reactants greater than the reactants dependent upon the presence of a catalyst

Consider the reaction of a(g) + b(g) + c(g) => d(g) for which the following data were obtained: experiment initial [a], mol/l initial [b], mol/l initial [c], mol/l initial rate, mol/l.s 1 0.0500 0.0500 0.0100 6.25 x 10^-3 2 0.100 0.0500 0.0100 2.50 x 10^-2 3 0.100 0.100 0.0100 1.00 x 10^-1 4 0.0500 0.0500 0.0200 6.25 x 10^-3 what is the rate law for the reaction?

Answer asap : ( a. how does mucus prevent the entry of pathogens? b. describe two ways white blood cells protect us from pathogens.