46. Which of the following statements most accurately reflects the known composition and mobility mechanisms of the repetitive DNA sequences that account for the largest proportion of the human genome? (A) Transposons (DNA intermediate) are the most abundant mobile element, responsible for 44% of the genome, moving via the cut-and-paste mechanism. (B) Simple sequence DNA (short tandem repeats, STRs) constitute 17% of the genome and primarily facilitate unequal crossing over to drive gene duplication. (C) The Alu elements (10% of the genome) are the largest type of retrotransposon and encode their own reverse transcriptase for movement. (D) Retrotransposons are the most abundant category, and unlike transposons, their movement inherently involves synthesizing a complementary DNA strand from an RNA intermediate, thus leaving a copy at the original location. (E) Transposable elements are included in the 1.5% of the genome that codes for proteins because they all encode the transposase or reverse transcriptase enzymes necessary for their own movement.