DNA is made of a "code" of 4 bases, A: Adenine, T: thymine, C:cytosine and G: guanine. This code is decoded by machines called ribosomes in your cells and every other cell. The code is universal because if AGG means something in your cells, it means the same thing to a fly decoding machine and a mouse decoding machine and a bacterial decoding machine too. Hope this helps :) tweet me if it doesn't.
