Concept:Reactions are classified by whether they absorb or release heat.Explanation:When heat is absorbed during a reaction, the enthalpy change is positive: ΔH>0. Such a reaction is described as endothermic because it takes in energy from the surroundings. Exothermic reactions release heat, while isothermal processes occur at constant temperature. Therefore, the correct term for a reaction that absorbs heat is endothermic.Answer:D. endothermic