An animal body that can be cut along its axis in any plane to give two identical parts is said to be

Analyze the question: The body can be cut along its axis in any plane and still give two identical halves. We need the term for this type of symmetry.

Explain the concept: Symmetry describes how body parts are arranged around a central point or axis.

• Radial symmetry: The body parts are arranged around a central axis, like spokes of a wheel. Cutting through the centre in any plane along that axis gives two identical halves. Examples: Hydra, sea anemone, jellyfish, starfish.
• Bilateral symmetry: The body can be divided into two mirror-image halves in only one plane (the sagittal plane, from head to tail). Examples: humans, goats, lizards, insects.
• Asymmetry: The body cannot be divided into two identical halves in any plane. Example: sponges (most species), snails in some cases.
• Symmetrical: A general term that doesn't specify the type, so it is not specific enough here.

Solution:

1. The question says "any plane" along the axis, which means many cutting planes work.
2. Only radial symmetry allows this, because the body is built around a central axis.
3. Bilateral symmetry allows only one plane, so B is out.
4. Asymmetrical bodies cannot be divided equally at all, so C is out.
5. "Symmetrical" (D) is too general and is not the specific answer.

Answer: A. radially symmetrical

Tip: Think of a pizza or a wheel: you can slice it through the centre at any angle and get equal halves, which is radial symmetry. Think of a human face: only one vertical line gives matching halves, which is bilateral symmetry. The key phrase to look for is "any plane", which points to radial symmetry.