2. If there are 20 chromatids in a cell, how many centromeres are there?

10 centromeres

Explanation: Meaning that the normal number of chromosomes in the cell should be 10 and there should normally be 5 chromosome pairs. Now that there are 20 chromatids they should be in identical pairs of 2 (sister chromatids) as they have undergone replication. Therefore there would be 10 centro-meres

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this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.

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