Which of these is a major drawback of using fuel cells in a car? A. a lack of hydrogen filling stations
B. a drop in reliance on petroleum products
C. an increase in water vapor into the atmosphere
D. an increase in the use of rechargeable batteries

Which object forms when a supergiant runs out of fuel? a red giant a black hole a white dwarf a neutron star

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Adilute aqueous potassium nitrate solution is