Answer:
Massive stars transform into supernovae, neutron stars and black holes while average stars like the sun, end life as a white dwarf surrounded by a disappearing planetary nebula. All-stars, irrespective of their size, follow the same 7 stage cycle, they start as a gas cloud and end as a star remnant.
Explanation:
Answer:
Early cyanobacteria in stromatolites are thought to be responsible for increasing the amount of oxygen in the primeval Earth's atmosphere through their continuing photosynthesis. They were the first known organisms to photosynthesize and produce free oxygen.
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Answer:
Yes.
Explanation:
If the graph line comes lowers from 1999 to 2013 so it means that steps taken by the EPA and the factories were effective in reducing air pollution. The steps taken by the EPA and the factories were effective in reducing air pollution occurs from two pollutants i. e nitrogen oxides (NOx) and sulfur dioxide (SO2) if they install chimneys which collect these gases and reduce pollution. if the factories uses coal having less concentration of sulphur so less air pollution occurs.
