1. What are the two sources of thermal energy in Earth's interior?
A. solar heating and gravity
B. combustion and solar heating
C. gravity and radioactive decay
D. radioactive decay and combustion

c

radioactive

decay is the process by which an unstable atomic nucleus loses energy by radiation

idk i’m struggling too

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.