The public is not yet able to purchase cars powered by hydrogen fuel cells because engineers have to determine how the cars perform based on which scenario? on racetracks in real-world conditions in flooded environments on closed courses A(on racetracks
B(in real-world conditions
C(in flooded environments
D(on closed courses

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.