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.
The border separates Sonora and Chihuahua is Natural boundary
The air and water are polluted
<span>d.rainwater evaporates from puddles.</span>
