D. a new substance is formed. if it is chemical change then it is actually changing to something new. In this case a new substance is formed. It is a completely different substance from what you started out with.
They should study about how volcanoes erupt or explodes
Answer: Twice
Explanation: With quadratic functions they are usually represented by parabolas and they can cross the x axis only once or twice :)
Answer:
Which statement describes clean air as a natural resource?
Clean air reduces the risk of illnesses and other health problems.
