Answer: The Precambrian Era comprises all of geologic time prior to 600 million years ago.
Explanation: The Precambrian was originally defined as the era that existed before the emergence of life in the Cambrian Period. It is known that life on Earth began by the early Archean and that fossilized organisms became more and more abundant throughout Precambrian time.
Answer:
the I think it's because of better educational and job prospects because in the rural areas people there have poor educational centres and some of the jobs don't give enough payment to support their families so they moved to the Urban areas where they can get better education and better jobs too
Roosevelt choose to use such emotional language in the four freedoms speech because he needed to appeal the people's emotions to make them feel something so that they'd listen to him.