The organism that has DNA most similar to the bird is a crocodile.
The full form of DNA should be deoxyribonucleic acid representing the molecule that comprises of the genetic code of organisms. This involved animals, plants, bacteria. etc. Also, it should be in the each and every cell in the organism.
Also, the crocodiles should be the closest living relative as compared to the birds that shared the common ancestor which live approx 240 million years ago.
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