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5 votes
Which of these follows a cyclical pattern?

A. sunspot maxima and minima
B. condensation of a nebula
C. formation of a crater
D. formation of a black hole

1 Answer

4 votes
The number of sunspots, observed during the past 300 years or so,
has been found to vary up and down in a cycle of very very roughly
about 11 years.
User Alexandre Lavoie
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