For the equation 3Cu + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O, how many units of NO3 are represented on the products side? I never learned what parentheses mean in chemical reactions

Well anyway no assumptions and no links

introduction of a drug directly into the respiratory tract is a form of inhalation administration.

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.