Three of the following are base units used in the metric system. which is not a base unit? meter liter kilogram gram

Which type of reaction always has an element and a compound as reactants

What causes different colors to appear in the sky? the absorption of light by air molecules the reflection of light by bodies of water the greenhouse effect in earth's atmosphere the scattering and reflection of light by dust particles

Harry lives in a city, and he has a lung condition known as asthma. on certain days, harry has to stay inside because pollutants in the air make it difficult for him to breathe. which of these pollution sources are nonpoint sources that might bother harry if he goes outside? choose the two that apply.