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MCQIntermediateGalaxies & Universe
IAAC — 2021 Final Round
Question 32
In which one of the following time frames after the Big Bang did the cosmic reionization process begin?
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Source
Source: International Astronomy and Astrophysics Competition (IAAC), Final Round 2021. Question wording and answer-choice text are transcribed from the official training PDF; the explanation and metadata are original. The supplied official solution PDF lists answer keys only through Question 30; this answer is independently derived.