The top routes that United Airlines flies are: 1  CLT to ORD with 3,755 flights per month. 2  CLT to IAH with 3,511 flights every month. 3  DFW to ORD with 3,486 flights every month.  DFW to EWR with 3,268 flights every 1  month. PHL to ORD with 3,238 flights every month.
The first of the three rock types to form on Earth were the igneous rocks; formed from the cooling and solidification of magma, as the Earth was at one time completely molten. â¦. 4 people found this useful.
The oldest rocks and minerals on Earth Exhibition Text Much of the evidence from the oldest period of the Earthâs history, the Hadean era (3.8 to 4.5 billion years ago), has been destroyed by erosion, burial, and modifications of the rocks as they were heated and compressed at depth. Yet clues can be found in the durable mineral zircon.