4.6 billion years ago - most likely hydrogen (H2) and helium (He)
probably rich in hydrogen compounds like methane (CH4), ammonia (NH3), hydrogen cyanide (HCN), water (H2O), and formaldehyde (HCHO). Also some N2, CO2 but LITTLE or NO free oxygen.
Molecules of H2 and He move really fast, especially when warm, that they eventually all escaped Earth's gravity and drifted off into space.
On it's tectonic plates pressure of magma forcing to the earth surface
Answer:
because it begins where there is no soil. It can take several hundred to several thousand years to produce fertile soil naturally. The first pioneer species to colonize the bare rock will probably be bacteria and lichens, which can live without the soil.