<span>Scientists choose where are units of time began and ended based on major changes in life forms at certain times</span>
China and Japan I hoped this helped :)
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c</span><span>A. grow larger
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The mass of the star actually determines the stage of the star after supernova. If the mass of the star is small, then it would become a very small and dwarf, cold and dead body in space. The mass of the star has to be less than that of the sun. If the mass of the star is greater than sun, then it would become a black hole. The mass of the star has to be more than 1.4 times the mass of the sun to become a black hole.
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Nebula is the cloud of interstellar dust and gas that forms a star. It is collborately shaped during colliding and collapsing of the interstellar mediums this is influenced by the gravitational attraction of the atoms and particles in the entites. Hence, there are three types of nebular namely, are classical nebula, diffuse nebula, planetary nebular and supernova remnants.
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Characteristics of a rejuvenated river include water that flows rapidly with sloping sides that create steep cuts on the valley floor.
