I need some help with this

State the formula for density in words and mathematical symbols

When a comet collides with earth, it adds material to our planet and causes great damage. therefore, a collision like this is a a. destructive force b. constructive force c. geologic process and event d. constructive and destructive force

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )