Temperature inversions: O
allow cool and warm air to mix in the atmosphere, clearing air pollution.
trap cooler air and pollutants closer to the ground, making air pollution worse.
shift pollution from the lower atmosphere to the upper atmosphere.
None of these choices are correct.

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.