Which of the following atmospheric components is beneficial to humans at higher altitudes, but dangerous near ground level? A. carbon dioxide
B. sulfuric acid
C. oxygen
D. ozone

What is a property of a double replacement reaction

Clyde and marilyn are riding a roller coaster. during which section(s) of the track is their potential energy converted to kinetic energy? a. from point b to point c only b. from point b to point d only c. from point a to point b only d. from point a to point b and from point c to point d

Elements in group 2 are all called alkaline earth metals. what is most similar about the alkaline earth metals?