### animal:

Cnidarian
* All cnidarians are acoelomate
  - carnivorous, with cnidae and tentacles active in prey capture
* All cnidarians have a mouth in the center of their bodies, surrounded by tentacles
  - tentacles which are located around their mouths and contain stinging cells
* Many cnidarians are able to propagate asexually, for example by budding in Hydra.
* Most cnidarians are carnivorous and feed on small crustaceans
  - dioecious
  - marine, although a few, such as the well-known hydra, are freshwater species
* Most cnidarians have body cavities
  - inhabit environments
  - reproduce by budding
* Some cnidarians alternate between polypoid and medusoid forms during their life cycle
  - are polymorphic, having two body plans during their life cycle
  - divide in two
  - feed on shrimp
* Some cnidarians have adults
  - contractile fiber
  - ecological significance
  - economic importance
  - either medusa or polyp stages, or both, in their life cycles
  - particular ecological significance
  - sacs
  - sessile adults
  - surfaces
  - possess tissue
  - prey on fish
* Some cnidarians rely on diffusion
  - simple diffusion
  - use molecular methods
* also lack certain tissue types found in other animal phyla, such as true muscle cells.
* are a diverse group of aquatic animals
  - group of invertebrates that includes jellyfish, corals, sea anemones, and hydras
  - all aquatic and mostly marine
  - almost all marine carnivores
  - also diploblastic , with only ectoderm and endoderm as tissues
  - animals with stinging cells called cnidoblasts
  - aquatic, mostly all marine
  - both sessile and motile with forms including jellies, corals, and hydras
  - carnivores that use their tentacles to catch prey
  - carnivorous, the major part of their diet consisting of crustaceans
* are diploblastic, meaning that they only have an endoderm and ectoderm
  - so they lack organs
  - entirely aquatic animals
  - essentially bags made of two cell layers
  - gonochoristic
  - incredibly diverse in form
  - known for their radially symmetrical and the tentacles that encircle their mouth
  - predators that use special stinging cells to subdue their prey
  - radial, tentacled animals that live mostly in the seas
* are radially symmetrical and they have tentacles that encircle their mouth
  - invertebrates with two tissue layers
  - said to be the simplest organisms at the tissue grade of organization
  - the scientific group of animals which contain corals
* are the simplest animals in which the cells are organised into tissues
  - with cells organised into tissues
  - widespread in marine habitats and less common in fresh water
* can have a polyp phase , medusa phase , or both, in their life cycles.
* comes from a Greek word meaning stinging nettles.
* digest food.
* exhibit radial or biradial symmetry around a longitudinal axis
  - two basic structural forms, a medusa and a polyp
* exist as either polyps or medusae, or both in alternation.
* feed using tentacles that are embedded with stinging nematocysts.
* have a digestive cavity and carry out extracellular and intracellular digestion
  - hydrostatic skeleton
  - nervous system, including simple sense organs
  - radially symmetrical body shape with a mouth surrounded by rings of tentacles
  - true mouth and digestive cavity, but no anus
  - an ectoderm and endoderm, both of which are germ layers
* have both sexual and asexual forms of reproduction
  - reproduction cycles
  - many specialized features, including tentacles, stinging cells, and net nerves
  - more than three true tissue layers
  - radial symmetry and are sessile or free-floating as adults
* have stinging cells, called nematocysts, which are used for defense
  - organelles called nematocysts and has polymorphism
  - organelles, unlike Ctenophores
* have two basic body forms, medusa and polyp
  - possible body types a medusa and a polyp
* includes brains
  - cell membranes
  - coelenterons
  - corpi
  - cytoplasm
  - ears
  - heads
  - nuclei
  - plasma membranes
  - sections
  - skulls
  - vacuoles
* is an invertebrate
* lack organs and posses a primitive nervous system known as a neural net.
* possess only one digestive opening, which serves as both the mouth and the anus
  - radial symmetry and can be divided like a pizza, all slices being equal
  - special cells called cnidocytes that are especially abundant in the tentacles
* reproduce both sexually and asexually
  - in different ways depending on whether they are polyps as adults, or medusae
* use asexual and sexual reproduction
  - tentacles with stinging cells called nematocysts to capture food
  - their nema- tocysts primarily to capture prey