How has gene duplication played a critical role in evolution? see concept 21.5 (page 452)?

During sunny hours, a large amount of build up between the hours of 1: 00-5: 00 pm. a. ozone b. mercury c. lead d. sulfuric acid

Which best explains why there are 64 possible codons in the genetic code and only 20 amino acids that make protiens of living organisms on earth

The empty trna moves off and picks up another matching amino acid from the cytoplasm in the cell. the anticodon of the trna, with its attached amino acid, pairs to the codon of the mrna, which is attached to a ribosome. this sequence is repeated until the ribosome reaches a stop codon on the mrna, which signals the end of protein synthesis. the ribosome forms a peptide bond between the amino acids, and an amino acid chain begins to form. when a second trna with its specific amino acid pairs to the next codon in sequence, the attached amino acid breaks from the first trna and is bonded to the amino acid of the second trna.