What are some of the different substances that make up a pizza​

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

particle   p is an electron and particle q is a neutron

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.