Polymers are formed by joining several units called monomers. what does the term monomer refer to?
a) a unit made up of several compounds.
b) a unit made up of several atoms.
c) a unit made up of several molecules.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

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

explanation: