Context: Chimaeras are cartilaginous fishes in the order Chimaeriformes, known informally as ghost sharks, rat fish (not to be confused with the rattails), spookfish (not to be confused with the true spookfish of the family Opisthoproctidae), or rabbit fish (not to be confused with the true rabbitfishes of the family Siganidae)., In cryptography, SHARK is a block cipher identified as one of the predecessors of Rijndael (the Advanced Encryption Standard)., A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water and excretes carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment., Sawfishes, also known as carpenter sharks, are a family of rays characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged so as to resemble a saw. Several species of sawfishes can grow to about . The family as a whole is largely unknown and little studied. The Pristidae are the only living family within the order Pristiformes, whose name comes from the ., A clade (from , "klados", "branch") is a group of organisms that consists of a common ancestor and all its lineal descendants, and represents a single "branch" on the "tree of life"., Neoselachii are a grouping of cartilaginous fishes in subclass Elasmobranchii of class Chondrichthyes . It contains all living ( extant ) sharks , skates , and rays ., Chondrichthyes (from Greek - "chondr-" 'cartilage',  "ichthys" 'fish') is a class that contains the cartilaginous fishes: they are jawed vertebrates with paired fins, paired nares, scales, a heart with its chambers in series, and skeletons made of cartilage rather than bone. The class is divided into two subclasses: Elasmobranchii (sharks, rays, skates, and sawfish) and Holocephali (chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class)., A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fish, cetaceans (whales, dolphins, and porpoises), and the (extinct) ichthyosaurs. Depending on the species, an animal may have one or two of them. , Elasmobranchii is a subclass of Chondrichthyes or cartilaginous fish. Members of this subclass are characterised by having five to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins and small placoid scales on the skin. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper. The details of this jaw anatomy vary between species, and help distinguish the different elasmobranch clades. The pelvic fins in males are modified to create claspers for the transfer of sperm. There is no swim bladder, instead these fish maintain buoyancy with large livers rich in oil., The subclass Holocephali ("complete heads") is a taxon of cartilaginous fish in the class Chondrichthyes. The earliest fossils are of teeth and come from the Devonian period. Little is known about these primitive forms, and the only surviving group in the subclass is the order Chimaeriformes. This group includes the rat fishes in the genus "Chimaera", and the elephant fishes in the genus "Callorhynchus". These fishes move by using sweeping movements of their large pectoral fins. They have long slender tails and live close to the seabed feeding on benthic invertebrates. They lack a stomach, food moving directly into the intestine., Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones). Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 64,000 species described. Vertebrates include the jawless fish and the jawed vertebrates, which include the cartilaginous fish (sharks and rays) and the bony fish. , The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of many bony fish (but not cartilaginous fish) to control their buoyancy, and thus to stay at their current water depth without having to waste energy in swimming. Also, the dorsal position of the swim bladder means the center of mass is below the center of volume, allowing it to act as a stabilizing agent. Additionally, the swim bladder functions as a resonating chamber, to produce or receive sound., In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating., Cartilage is a resilient and smooth elastic tissue, rubber-like padding that covers and protects the ends of long bones at the joints, and is a structural component of the rib cage, the ear, the nose, the bronchial tubes, the intervertebral discs, and many other body components. It is not as hard and rigid as bone, but it is stiffer and less flexible than muscle., Sperm is the male reproductive cell and is derived from the Greek word () "sperma" (meaning "seed"). In the types of sexual reproduction known as anisogamy and its subtype oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell. A uniflagellar sperm cell that is motile is referred to as a spermatozoon, whereas a non-motile sperm cell is referred to as a spermatium. Sperm cells cannot divide and have a limited life span, but after fusion with egg cells during fertilization, a new organism begins developing, starting as a totipotent zygote. The human sperm cell is haploid, so that its 23 chromosomes can join the 23 chromosomes of the female egg to form a diploid cell. In mammals, sperm develops in the testicles and is released from the penis. It is also possible to extract sperm through TESE. Some sperm banks hold up to of sperm., A bone is a rigid organ that constitutes part of the vertebrate skeleton. Bones support and protect the various organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have a complex internal and external structure. They are lightweight yet strong and hard, and serve multiple functions. , Subject: neoselachii, Relation: instance_of, Options: (A) area (B) biology (C) block cipher (D) bone (E) cage (F) cell (G) cipher (H) clade (I) class (J) cryptography (K) elephant (L) environment (M) extension (N) family (O) fish (P) five (Q) food (R) gas (S) ghost (T) limited (U) mass (V) may (W) muscle (X) oil (Y) opening (Z) order ([) organ (\) organism (]) part (^) period (_) rat (`) reproduction (a) saw (b) seed (c) size (d) skeleton (e) sound (f) species (g) store (h) subtype (i) swimming (j) taxon (k) tissue (l) tree of life (m) two (n) variety (o) water (p) word
Output: clade