Question

In a bilaterally symmetrical animal, how many planes (flat surfaces) are used to divide the organism into specific parts?

1) One plane
2) Two planes
3) Three planes
4) Four planes

Answer 1

A bilaterally symmetrical animal can be divided into mirror image left and right sides by a single plane, called the midsagittal plane. The correct option is 1.

Step-by-step explanation:

In a bilaterally symmetrical animal, there is only one plane that can be used to divide the organism into specific parts, where that plane creates distinct left and right sides that are mirror images of each other. This plane is known as the midsagittal plane. It runs from the front (anterior) to the back (posterior) of the organism.

This type of symmetry is characteristic of animals with an organized head and tail and allows for streamlined and directional motion. The correct option is 1.