An endothermic reaction is a chemical process that absorbs heat from its surroundings. This means that during the reaction, the temperature of the surrounding environment decreases. Common examples include photosynthesis, where plants absorb sunlight to convert carbon dioxide and water into glucose and oxygen. In an endothermic reaction, energy is required to break bonds in the reactants, leading to the formation of products. The absorbed energy is often in the form of heat, which is why these reactions can feel cold to the touch. Understanding endothermic reactions is essential in fields like chemistry and environmental science.