Is air an element, compound, homogeneous mixture, or a heterogeneous mixture?

Two things that biomedical has invented or innovated

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

Amap that uses a range of colors and shading to represent the elevation, depth, or landscape of specific features on earth is a/an map.