As Earth Evolved with Life, an Oxygen Abundance of Only

question 38

Short Answer

As Earth evolved with life, an oxygen abundance of only 0.1 percent would have created a(n) _______________, protecting organisms from the Sun's ultraviolet radiation.

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Definitions:

Diagnosed

The process of identifying a disease or condition from its signs and symptoms by using a range of assessments, including medical history, tests, and procedures.

Italicized Brackets

Brackets ([ ]) used in printed text, typically emphasized by being sloped to the right to denote a special meaning or context.

Brackets

Punctuation marks used in pairs to group words together or clarify meaning, including square, round, curly, and angle brackets.

Parentheses

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