The coolest layer is the crust. The crust is on the surface of the earth (where we are) . Inner Core
A city that has a problem with smog is most likely a MDC and is experiencing it due to heavy air pollution. <span />
Answer:
A i think, sorry if im wrong.
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.
