What is an exothermic reaction and an endothermic reaction?

(N/A) $1$. Exothermic Reaction: $A$ chemical reaction in which energy is released into the surroundings,usually in the form of heat or light. In these reactions,the total energy of the products is less than the total energy of the reactants. Example: Combustion of methane,$CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O + \text{Heat}$.
$2$. Endothermic Reaction: $A$ chemical reaction in which energy is absorbed from the surroundings. In these reactions,the total energy of the products is greater than the total energy of the reactants. Example: Photosynthesis,$6CO_2 + 6H_2O + \text{Energy} \rightarrow C_6H_{12}O_6 + 6O_2$.