In studies using repeating copolymers, AC . . . incorporates threonine and histidine, and CAACAA . . . incorporates glutamine, asparagine, and threonine. What triplet code can definitely be assigned to threonine?

ACA

Explanation:

From the repeating polymer

ACACA one can say that threonine is either CAC or ACA.

From the polymer CAACAA with ACACA, CA is the only codon in common.

So therefore, threonine will have the codon ACA.

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explanation:

i was told this before by a teacher, so yeah

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.