Solution:
Concept: A reaction where atoms combine is combination reaction, when the reactants absorb heat, then it is said to be as endothermic reaction.In a chemical reaction, reactants undergo a chemical reaction and transform into products through a chemical process. There are various kinds of chemical reactions. The ones that were stated above will be discussed here.
1) Two or more molecules combine chemically to create a new substance in a combination reaction (compound). Reactions of combination and breakdown are in opposition to one another.
2) In the course of endothermic reactions, energy is absorbed. For this, the enthalpy of products is higher than the enthalpy of reactants.
On the other hand, Exothermic reactions are those in which heat is released that is, the enthalpy of products is less than that of reactants.
Hence, the correct answers are combination and endothermic reaction, respectively.