Organism > System > Organ > Tissue > Cell > Molecule > Atom
Answer:
The hardness rating is 4.
Explanation:
Calcite sits at a hardness rating of 3 and is very easily scratched with a knife and/copper coin. This is where most Marbles, limestones, travertines, rate.
Meanwhile, Fluorite sits at hardness 4 and can be scratched by a knife.
Explanation:
The giant-impact hypothesis is currently the favored scientific hypothesis for the formation of the Moon. Supporting evidence includes: Earth's spin and the Moon's orbit have similar orientations. Moon samples indicate that the Moon's surface was once molten.
Answer:
water
Explanation:
Water puts out fire by creating a barrier between the fuel source and the oxygen source (it also has a cooling effect which has to do with the energy required to convert liquid water into water vapor). It does this because it is a completely, 100% oxidized material. It simply cannot oxidize any further so it will not “burn”. This smothers the fire. The same thing would happen if you used the ashes that remained after a completely spent fire. Or, as I mentioned before, CO2.