The ozone layer does indeed block approximately 99% of the Sun's harmful ultraviolet radiation, forms in the stratosphere through the reaction of free oxygen atoms with oxygen gas molecules, and has been depleting due to human activities but is on a recovery path, projected to return to its 1980 levels by around 2050, thanks to global efforts like the Montreal Protocol.

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The Ozone Layer

Question 26

Multiple Choice

The ozone layer

A) prevents 99 % of the ultraviolet radiation produced by the Sun from reaching Earth.
B) forms in the stratosphere when free oxygen atoms combine with oxygen gas molecules.
C) has been depleted for decades but is projected to recover to 1980 levels by 2050.
D) All of these are correct.

Correct Answer: