I don't know how things work in Dallas but in Houston the EZ Tag is only good for one vehicle. Apparently quite often the tag doesn't get read and they have to go from a photo of the license plate. Only one plate number is matched to each toll tag and if your plate isn't in their database you get a fine plus the normal fee.
In general, biology recognizes the cell as the basic unit of life, genes as the basic unit of heredity, and evolution as the engine that propels the synthesis and creation of new species.
Definition of DNA for English Language Learners. : a substance that carries genetic information in the cells of plants and animals.