Question: Information: - Hydroida is an obsolete cnidarian order which united such animals as hydras , hydromedusae , and many marine attached hydroids . However , the group is paraphyletic and not composed from close relatives . But for the largest part , this group makes up what today is usually considered the subclass Leptolinae ( or Hydroidolina ) which also includes the colonial jellies of the Siphonophora which were not part of the Hydroida . The '' hydroid '' cnidarians typically which grow up into large , elegantly branched forms . All the zooids of a colony are asexually produced from one parent zooid . Examples of '' hydroids '' are : Craspedacusta sowerbyi , the freshwater '' jellyfish '' Hydra Air ferns , novelty '' plants '' and aquarium ornaments . Obelia Aequorea victoria of the suborder Leptomedusae , the crystal jelly - a bioluminescent jellyfish . - Hydrozoa (hydrozoans, from ancient Greek , "hydra", "sea serpent" and , "zoon", "animal") are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most living in salt water. The colonies of the colonial species can be large, and in some cases the specialized individual animals cannot survive outside the colony. A few genera within this class live in fresh water. Hydrozoans are related to jellyfish and corals and belong to the phylum Cnidaria. - Leptolinae (or Leptolina) are a subclass of the Hydrozoa class in the cnidarian phylum. They contain the bulk of the paraphyletic "Hydroida" which were one of the main groupings of the Hydrozoa in older classifications and were placed at order rank. They also include, however, the highly advanced colonial jellies of the Siphonophora, which were not included in the "Hydroida". - In biology, a phylum (plural: phyla) is a taxonomic rank below kingdom and above class. Traditionally, in botany the term division was used instead of "phylum", although from 1993 the International Code of Nomenclature for algae, fungi, and plants accepted the designation "phylum". Depending on definitions, the kingdom Animalia contains approximately 35 phyla, Plantae contains about 12, and Fungi contains around 7. Current research in phylogenetics is uncovering the relationships between phyla, which are contained in larger clades, like Ecdysozoa and Embryophyta. - Cnidaria is a phylum containing over 10,000 species of animals found exclusively in aquatic (freshwater and marine) environments: they are predominantly marine species. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick. They have two basic body forms: swimming medusae and sessile polyps, both of which are radially symmetrical with mouths surrounded by tentacles that bear cnidocytes. Both forms have a single orifice and body cavity that are used for digestion and respiration. Many cnidarian species produce colonies that are single organisms composed of medusa-like or polyp-like zooids, or both (hence they are trimorphic). Cnidarians' activities are coordinated by a decentralized nerve net and simple receptors. Several free-swimming species of Cubozoa and Scyphozoa possess balance-sensing statocysts, and some have simple eyes. Not all cnidarians reproduce sexually, with many species having complex life cycles of asexual polyp stages and sexual medusae. Some, however, omit either the polyp or the medusa stage. Given the information above, choose from the list below the object entity that exhibits the relation 'parent taxon' with the subject 'hydroida'. Choices: - animal - bear - cnidaria - ecdysozoa - fungi - hydra - hydroida - hydrozoa - leptolinae - phyla
Answer:
hydrozoa