(Choice A) The genetic code is not ambiguous as each codon is associated with only a single amino acid.
(Choice B) The genetic code is read sequentially from a starting point and has no internal punctuation as each codon is adjacent to the next without spacer nucleotides in between.
(Choice C) Genetic transition refers to a point mutation that results in replacement of a purine nucleotide for another purine or a pyrimidine nucleotide for another pyrimidine. In contrast, transversion refers to a point mutation that results in the replacement of a purine nucleotide for a pyrimidine or a pyrimidine nucleotide for a purine.
(Choice D) The genetic code is almost universal as amino acid codons are nearly identical across species; however, mitochondria and some bacteria and single-celled eukaryotes deviate from the standard genetic code.

(Choice A) Charged tRNA delivers amino acids to the protein synthesis complex. The anticodon on a tRNA molecule recognizes the corresponding codon on mRNA, assuring proper amino acid sequencing.
(Choice B) Elongation factors facilitate tRNA binding and the translocation steps of protein synthesis.
(Choice D) Transcription produces a pre-mRNA molecule containing both introns and exons. Splicing is a posttranscriptional modification in which intrans are removed from pre-mRNA via small nuclear ribonucleoproteins (snRNPs).
(Choice E) Initiation of gene transcription is governed by the binding of transcription factors to the regulatory region of the gene. Transcription factor II D binds to the TATA promoter sequence located – 25 bases upstream from the coding region of the gene.
(Choice F) During protein synthesis, uncharged tRNA (lacking an amino acid) does not interact with mRNA and ribosomes.

(Choices A, B, C, 0, and F) Homeobox genes do not typically encode cell surface receptors, cytoplasmic enzymes, DNA replication enzymes, structural proteins, or transport proteins.