Which one of the following substances is an element?

You 4. you have been swimming in your neighbor’s pool for an hour. the relative humidity of the air is 30 percent. will you feel warm or cool when you step out of the pool? explain your answer.

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

What are several ways to reduce the effect of friction