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Author Question: When did the ozone layer become thick enough to provide an effective UV screen? What will be an ... (Read 9 times)

SO00

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on: Jul 14, 2018
When did the ozone layer become thick enough to provide an effective UV screen?
 
  What will be an ideal response?

Question 2

During the Soviet era, every Central Asian republic capital had a(n) ________.
 
  A) Orthodox Christian cathedral
  B) mosque converted to city hall
  C) opera and ballet theater
  D) statue of Lenin posing with a local legendary hero


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k2629

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Reply #1 on: Jul 14, 2018
Answer to Question 1

The O3 layer should have been absorbing most UV radiation by 2.3 Ga, as soon as O2 levels began to rise. An O2 level of 1 PAL is sufficient to create an efficient ozone screen.

Answer to Question 2

C


SO00

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Reply 2 on: Jul 14, 2018
Wow, this really help

daiying98

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Reply 3 on: Yesterday
Excellent

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