If a piece of sea floor has moved 50 km in 5 million years, what is the yearly rate of sea-floor motion?

Ineed to find the answer of this question because i dont understand it

Select the word from the list that best fits the definition the nuclear family into which a person is born or adopted.

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.