- A nerve net
- A dorsal hollow nerve cord
- Ladder-like nervous system
- A single ganglion
No category found.
- Planula
- Polyp
- Medusa
- Hydroid
- Annelida
- Mollusca
- Platyhelminthes
- Nematoda
- Monotremes
- Marsupials
- Placentals
- All mammals
- Running
- Burrowing
- Flight muscle attachment
- Swimming
- Water absorption
- Gas exchange
- Preventing water loss
- Sensing vibrations
- Operculum
- Swim bladder
- Lateral line
- Cloaca
- Coelacanth
- Lamprey
- Shark
- Tuna
- Locomotion
- Feeding
- Defense and cleaning
- Reproduction
- Open
- Closed
- Absent
- Double
- Asexual fragmentation
- Budding
- Sexual reproduction with complex life cycles
- Binary fission
- Cnidaria
- Platyhelminthes
- Annelida
- Porifera
- Three germ layers
- Three body segments
- Three distinct cell types
- Three modes of reproduction
- Carnivora
- Primates
- Cetacea
- Pinnipedia
- Furcula
- Sternum (keel)
- Pygostyle
- Scapula
- Crocodilia
- Testudines
- Squamata
- Rhynchocephalia
- Notochord
- Gills
- Jaws
- Tails
- Cartilaginous skeleton
- Placoid scales
- Swim bladder
- Ampullae of Lorenzini
- Sessile
- Free-swimming
- Parasitic
- Terrestrial
