The complementary anticodon for the codon AAA is UUU. In the process of translation, the codon on the mRNA pairs with the anticodon on the tRNA. Since the codon AAA is composed of three adenine (A) bases, the complementary anticodon will consist of three uracil (U) bases, forming UUU.
This pairing is based on the rules of base pairing in RNA, where adenine (A) pairs with uracil (U). Therefore, the tRNA carrying the anticodon UUU will bind to the mRNA codon AAA, ensuring the correct amino acid is added to the growing polypeptide chain during protein synthesis.