Why was the precambrian era so long?

Because it started when the Earth was formed and ended when humans found good fossils. It is just a blank area.

Explanation:

Precambrian Oldest and longest era of Earth's history, lasting from the formation of the Earth c. 4.6 billion years ago to the beginning of a good fossil record c. 590 million

i am a little confused myself with what goes with the letters and what goes with the numbers but ill do my best to you

the cordillera states and grand canyon are along the southwest u.s. and northern mexican pacific.

the great plains and southwest desert are also the prairie and home to many earthquakes too .

the coastal plains have poor soil and many factories started in the south.

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