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.
there are three basic types of rocks that planet earth is composed of igneous sedimentary and metamorphic follow these simple guidelines to determine the three types of rocks when looking at various types of rocks in the fieldetamorphic rocks metamorphic rocks are types of existing rocks that have been altered in form as a result of changes in heat and pressure in mountainous regions for example where rock matter is pressed and altered by plate tectonic activity metamorphic rocks are very common