This reaction releases energy as heat explain whether the reaction is exothermic or endothermic and whether it obeys the law of conservation of energy.

The reaction that releases energy as heat is called an Exothermic reaction. This reaction does obey the law of conservation by preserving the energy present in the molecule and converting it to thermal heat to maintain it's from. Most reactions obey the law of conservation of energy.

i think it would be b. tissue because an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.