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.
When magma cools and hardens below the Earth's surface, an intrusive igneous rock forms. Because the process of the formation of intrusive igneous rock occurs slowly, these rocks tend to have a grainy texture.Examples of intrusive igneous rock include granite and gabbro.ocks are classified by the way they form. Igneous rocks are those that form when magma cools and hardens. This process can occur on the Earth's surface or underground. The exact location of the formation of the rock determines the type of igneous rock it is. Interesting Igneous Rocks Facts: