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.
Igneous Rocks. Igneous rocks are formed from lava or magma. Magma is molten rock that is underground and lava is molten rock that erupts out on the surface. The two main types of igneous rocks are plutonic rocks and volcanic rocks. Plutonic rocks are formed when magma cools and solidifies underground.Volcanic rocks are formed from lava that flows on the surface of the Earth and other planets and then cools and solidifies. The texture of an igneous rock depends on the size of the crystals in the rock.This tells us if the rock is plutonic or volcanic. When magma cools underground, it cools very slowly and when lava cools above ground, it cools quickly. When magma and lava cool, mineral crystals start to form in the molten rock.his tells us if the rock is plutonic or volcanic. When magma cools underground, it cools very slowly and when lava cools above ground, it cools quickly. When magma and lava cool, mineral crystals start to form in the molten rock.