Name a body part an animal has for fighting or protection

The rarest possible answer — almost no player finds it.

• Acrorhagi— Sea anemones wage slow border wars by clubbing neighbours with them.
• Cuvierian tubules— Some sea cucumbers eject these sticky organs to tie predators up.

Genuinely obscure. Most players never think of it.

• Acidopore
• Acontia
• Antennae
• Axial organ
• Blood-brain barrier
• Brille
• Bristles
• Bursa of Fabricius
• Casque
• Cell membrane
• Cerata
• Chloragogen tissue
• Cilia
• Coelomocytes
• Cornicles
• Cuticle
• Dactyl club
• Elytra
• Epigonal organ
• Eyes
• False head
• Fat body
• Forcipules
• Forelegs
• Frill
• Goblet cells
• Harderian gland
• Head kidney
• Hemocytes
• Hepatopancreas
• Insect lymph gland
• Interbranchial lymphoid tissue
• Intestines
• Keratinocytes
• Leydig's organ
• Mantle
• Meckel's diverticulum
• Meibomian glands
• Meninges
• Menisci
• Milky spots
• Mucosa-associated lymphoid tissue
• Mucous membranes
• Nasal turbinates
• Nasus
• Oka organ
• Omentum
• Operculum
• Orbital hood
• Paneth cells
• Pedicellariae
• Pericardium
• Peritrophic matrix
• Peyer's patches
• Photophores
• Poison glands
• Preen gland
• Proboscis
• Pronotum
• Radula
• Rump
• Sacculus rotundus
• Salmonid bursa
• Sclera
• Sebaceous glands
• Shoulder shield
• Siphon
• Slime glands
• Spinnerets
• Stomach
• Supraneural body
• Tegmina
• Thagomizer
• Thymoid
• Thymus
• Tongue
• Typhlosole
• Urticating hairs
• White body

Uncommon — only a minority of players land here.

• Abdomen
• Amniotic sac
• Appendix
• Armor
• Arms
• Blubber
• Bone marrow
• Cartilage
• Cervix
• Comb
• Cornea
• Electric organ
• Epiglottis
• Exoskeleton
• Feet
• Fists
• Foreskin
• Gills
• Gums
• Head
• Hood
• Hooks
• Hump
• Ink sac
• Intervertebral discs
• Kidneys
• Kneecap
• Lacrimal glands
• Legs
• Liver
• Lungs
• Lymph nodes
• Mammary glands
• Mandibles
• Neck
• Nematocysts
• Nostrils
• Paw pads
• Paws
• Penis— Flatworm fencing is exactly as awkward as it sounds.
• Pharynx
• Placenta
• Platelets
• Primordial pouch— Built-in belly padding. Its exact purpose is still debated.
• Rattle
• Red blood cells
• Ribs
• Rostrum
• Salivary glands
• Scales
• Scent glands
• Scrotum
• Skeleton
• Skin
• Sphincters
• Spleen
• Spurs
• Sternum
• Suckers
• Sweat glands
• Tail club
• Tear ducts
• Tonsils
• Trunk
• Uterus
• Venom glands
• Wattles
• White blood cells
• Wings

A solid, middling pick shared with plenty of other players.

• Beak
• Ears
• Eyelashes
• Eyelids
• Feathers
• Fins
• Flippers
• Hooves
• Jaws
• Pincers
• Pouch
• Quills
• Spines
• Tail
• Talons
• Tentacles
• Whiskers

The most common answer on the board.

• Antlers
• Claws
• Fangs
• Fur
• Horns
• Shell
• Stinger
• Teeth
• Tusks