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Author Question: Describe the conditions of Earth during the Precambrian. What will be an ideal ... (Read 28 times)

kfurse

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on: Jul 29, 2018
Describe the conditions of Earth during the Precambrian.
 
  What will be an ideal response?

Question 2

In radioactive decay, when the parent material decays to one-half of its original amount, the time is
 
  A) one half-life.
  B) two half-lives.
  C) three half-lives.
  D) four half-lives.


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momo1250

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Reply #1 on: Jul 29, 2018
Answer to Question 1

Answer: Hadean: intense volcanic activity, meteorite bombardment, precontinents in a state of constant change from internal and external forces.
Archean: gases from volcanic eruptions led to creation of a primitive atmosphere (rich in water, poor in oxygen) and the oceans. Blue-green algae, bacteria, and stromatolites were the first signs of life, organisms evolved a primitive form of photosynthesis, which later led to the development of the ozone layer.

Answer to Question 2

Answer: A


kfurse

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Reply #2 on: Jul 29, 2018
Both answers were spot on, thank you once again


momo1250

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Reply #3 on: Jul 29, 2018
Great! Please up vote :D


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