Which of the following represents the correct combination of a taxonomic group with its characteristics, without any exception?

All mammals possess mammary glands, lungs and undergo direct development. Some reptiles are aquatic (e.g., sea snakes, turtles). Electric organs are present only in some cartilaginous fishes (e.g., Torpedo); not all. Some amphibians are limbless (e.g., Ichthyophis).