Which type of reaction absorbs energy?

The type of reaction that absorbs energy is classified as endothermic. In an endothermic reaction, the system takes in energy from its surroundings, usually in the form of heat. This absorption of energy results in a decrease in the temperature of the surrounding environment, as the heat is drawn away to fuel the reaction.

Endothermic reactions contrast sharply with exothermic reactions, which release energy, typically in the form of heat or light, into their surroundings. Combustion, which is a specific type of exothermic reaction, releases energy by burning a fuel in the presence of oxygen. Oxidation can also involve energy exchange, but it does not specifically indicate the direction of energy flow; it can either release energy or require energy, depending on the reaction context.

By understanding that endothermic reactions require an intake of energy, one can see why the selected answer is the appropriate choice for identifying a reaction that absorbs energy.