EVERYDAY SCIENCE

Detailed explanation-1: -Cnidarians have a slightly more organized body plan, and have tissues, but no organs. Most cnidarians have two tissue layers. The outer layer, the ectoderm, has cells that aid in capturing food and cells that secrete mucus.

Detailed explanation-2: -All cnidarians have two tissue layers. The outer layer is called the epidermis, whereas the inner layer is called the gastrodermis and lines the digestive cavity. Between these two layers is a non-living, jelly-like mesoglea.

Detailed explanation-3: -All Cnidarians have tentacles with stinging cells in their tips which are used to capture and subdue prey. In fact, the phylum name “Cnidarian” literally means “stinging creature.” The stinging cells are called cnidocytes and contain a structure called a nematocyst.

Detailed explanation-4: -Cnidarians are radially symmetrical (i.e., similar parts are arranged symmetrically around a central axis). They lack cephalization (concentration of sensory organs in a head), their bodies have two cell layers rather than the three of so-called higher animals, and the saclike coelenteron has one opening (the mouth).

Detailed explanation-5: -Most species are marine, but hydras are freshwater forms. Cnidarians are have two true tissue layers (an outer epidermis and an inner gastrodermis) separated by a connective tissue layer called the mesoglea.