<span>An exothermic reaction is one in which there is the production of heat whereas an endothermic reaction is one in which heat is absorbed. For the choices above, the answer would be letter B. Ice melting in water and an ice pack turning cold absorbs heat which is why it is an endothermic reaction. Exploding fireworks and gasoline burning gives off heat which is why it is an exothermic reaction.</span>
The best answer to this question is DNA. DNA holds the genetic makeup of the body in each individual cell. RNA is part of DNA. The nucleus holds the DNA. Ribosomes turn RNA into protein. That is why the answer cannot be RNA, ribosomes, or the nucleus.
When two waves come in contact with each other while traveling on the same medium, its called constructive interference. Constructive interference happens when two waves come together.