Which system is responsible for the exchange of oxygen and carbon dioxide

Which step in naming unsaturated hydrocarbons is used for alkenes but not alkynes

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.

How are isotopes of the same element alike?