I think it's A but here's an explanation anyway: as you heat the crude oil, the different hydrocarbons, having different boiling points, boil and evaporate up the column. Those with lower boiling points, shorter in chain length, will condense nearer the top of the fractional distillation column. Those that are more viscous, larger in chain size, will have high boiling points, so will evaporate last and condense lower down in the column. Therefore, you achieve all the different oils / materials (oil, petrol, gasoline, tar etc etc). I hope this helps. If not, then a good website to use is 'BBC bitesize, fractional distillation'.
According to the ICSM (Intergovernmental Committee on Surveying and Mapping), there are five different types of maps: General Reference, Topographical, Thematic, Navigation Charts and Cadastral Maps and Plans.
<span>Romans
Phoenicians
Muslim Arabs</span>
The population of Oregon which is given above may also be expressed in scientific notation as,
4 x 10^6
The magnitude of this number is the exponent of 10 in the scientific notation. Thus, the answer is letter "B. 6".