Final answer:
In this question, we are discussing exothermic and endothermic reactions. Exothermic reactions release heat into the surroundings, while endothermic reactions absorb heat from the surroundings. Reaction A is exothermic, Reaction B is endothermic, and Reaction C remains at a constant temperature.
Step-by-step explanation:
Reaction A is exothermic because it releases heat, causing the surroundings to warm up. For example, when you put a pan of water on the stove and give it heat, the water boils and heat/energy is added, making the reaction endothermic. Reaction B is endothermic because it absorbs heat, causing the surroundings to cool down. When you burn something, it feels hot to you because it is giving off heat into the surroundings. Finally, Reaction C is exothermic because it remains at a constant temperature. For instance, when water is put into a freezer to freeze, heat is pulled out of the water, making it exothermic.