When do P waves arrive at the surface in relation to S waves and surface waves? ( Must be in your own words)

Why does a plastic bottle that is sealed at a high altitude change it’s shape when taken to lower altitude

What is a difference between a mixture of elements and a mixture of compounds

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.