The fossils that provide information on the formation of an oxygen-rich atmosphere are the stromatilites from the Precambrian era. These are layered and columnar fossils consisting mainly of cyanobacteria which were the original life form back then. These bacteria took in carbon dioxide and produced oxygen by photosynthesis as early as 2.5 billion years ago (the earth is about 4.5 billion yrs old).
An element have the same number of protons as electrons.
Therefore: if an element x (Lawrencium) has 103 protons, it has 103 electrons.
Answer:
in the cytoplasm; in the mitochondria
Explanation:
The answer is; Oil shale occurs only in areas with plentiful water resources for processing.
The refinement of oil shale requires a lot of water. This is used to quench the products of retorting and pyrolysis and also reduce dust. The water used becomes heavily polluted and has to be treated before discharge, otherwise, it will be the cause of a major environmental disaster to the local areas.
