Scientists can't be sure about the early atmosphere and can only draw evidence from other sources. For example, volcanoes release high quantities of carbon dioxide. Iron-based compounds are present in very old rocks that could only have formed if there was little or no oxygen at the time.
Extracting fossils fuels.Mining is used to extract solid fossil fuels such as coal by digging scraping or other wise exposing buried resources.Drilling methods help extract liquid or gaseous fossil fuels that can be forced to flow to the surface such as conventional oil and natural gas
Jobs that woman are doing pay less then men often times