Mutations and rearrangements that occur by misalignment during DNA replication are frequent sources of genetic variation in bacteria. Dislocations between a replicating strand and its template at repetitive DNA sequences underlie the mechanism of these genetic events.
Cnidarians take on two basic forms, a medusa and a polyp. The medusa form is a free-swimming structure which consists of an umbrella-shaped body (called a bell), a fringe of tentacles that hang from the edge of the bell, a mouth opening located on the underside of the bell, and a gastrovascular cavity. The mesoglea layer of the medusa body wall is thick and jelly-like.
Share. By Laura Klappenbach. Cnidarians (Cnidaria) are a group of aquatic animals that includes jellyfish, corals, sea anemones, and hydras. The basic form of the cnidarian body is quite simple and consists of a gastrovascular cavity with a single opening through which food is ingested and waste is released.nidarians are radially symmetrical and they have tentacles that encircle their mouth. The body wall of cnidarians consists of an outer layer or epidermis, an inner layer or gastrodermis, and a middle layer or mesoglea. Cnidarians lack organs and posses a primitive nervous system known as a neural net.