Question

Animals exhibiting .......... symmetry can be cut into two equal halves by one plane

• A. Spherical symmetry
• B. Radial symmetry
• C. Bilateral symmetry
• D. All of the above

Answer 1

The correct option is D All of the above

1. Spherical symmetry : In spherical symmetry the shape of the body is spherical and lack any axis. The body can be divided into two identical halves in any plane that runs through the organism’s cen­tre. It is seen in radiolarian protozoa.

2. Radial symmetry : In radial symmetry the body can be divided into two roughly equal halves by any one of many vertical planes passing through the central axis. The radial symmetry is seen among hydroids, anthozoan pol­yps, medusae and sea stars.

3. Bilateral symmetry : In bilateral symmetry the body parts are arranged in such a way that the animal is divisible into roughly mirror image halves through one plane. Bilaterally sym­metrical animals include acoelomates, pseudo-coelomates and eucoelomates among invertebrates and both lower chordates and vertebrates.

So, the correct option is 'All of the above'.