Final answer:
Transposons are segments of DNA that can move within a genome. They make up a significant portion of the non-coding DNA in maize and human genomes, with some organisms having transposons accounting for up to 80% of their genome. Transposons are primarily composed of repetitive DNA sequences.
Step-by-step explanation:
Transposons are segments of DNA that have the ability to move from one location to another within a genome. In maize and human genomes, transposons make up a significant portion of the non-coding DNA.
While the exact percentage can vary, transposons can account for as much as 80% of a genome in some organisms. These transposable elements are primarily composed of repetitive sequences of DNA.