Fossil fuel embedded energy is still photosynthetic in origin. Terrestrial plants, on the other hand, tended to form coal and methane. Many of the coal fields date to the Carboniferous period of Earth's history. Terrestrial plants also form type III kerogen, a source of natural gas. There is a wide range of organic, or hydrocarbon, compounds in any given fuel mixture. The specific mixture of hydrocarbons gives a fuel its characteristic properties, such as boiling point, melting point, density, viscosity, etc. Some fuels like natural gas, for instance, contain only very low boiling, gaseous components. Others such as gasoline or diesel contain
Interlanguage fossilization to learning second language, and the relationship of fossilization to the learner's communicative needs. Arguments have emerged regarding adult learners' general lack of empathy with target language native speakers and culture. According to Guiora et al., adults do not have the motivation to change their accent and to acquire native-like pronunciation. Unlike children, who are generally more open to target language culture, adults have more rigid language ego boundaries. Thus, adults may be inclined to establishing their pre-existing cultural and ethnic identity, and this they do by maintaining their stereotypical accent. Notwithstanding this, there is a lack of needed research,