AP BIOLOGY

Detailed explanation-1: -Radial symmetry is the arrangement of body parts around a central axis, like rays on a sun or pieces in a pie.

Detailed explanation-2: -Special forms of radial symmetry are tetramerism (having four identical parts around a central axis) and pentamerism (with five identical parts around a central axis). Biradial symmetry is a combination of radial and bilateral symmetries, such as that of ctenophores (comb jellies).

Detailed explanation-3: -The body of a person with radial symmetry has the general shape of a short or long cylinder or bowl, with a central axis from which the body parts radiate or are arranged in a regular pattern. As a result, the major axis is known as the oral-aboral (or anteroposterior) axis.

Detailed explanation-4: -In radial symmetry, the organism can be divided into more than two planes with identical pieces. Biradial symmetry is an intermediate where the organism can be divided, like radial symmetry, but in two planes only.

Detailed explanation-5: -Radial symmetry is found in the cnidarians (including jellyfish, sea anemones, and coral) and echinoderms (such as sea urchins, brittle stars, and sea stars).