The same gas that makes bread rise is also found in what?

Iknow #2 is d. i just need to know why

How many moles are in 250 grams of tungsten (w)? * 4.4x10^23 moles 4.2x10^23 moles 0.7 moles 1.4 moles

6what is the importance of water on earth? a) it keeps the top layer of the geosphere cool b) it allows life to exist c) it provides ice at the poles d) it creates earth's blue color from space