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.
Oldest Rocks On Earth. The oldest rocks are found in the cores of continents, and the youngest are in the rift valleys of mid-ocean ridges. they can be found at the tops of mountain ranges as well. some of the oldest rocks found on Earth can be found at the top of the Beartooth mountain range here in MT. Atlantic ocean.