It is the arrangement of similar organs in the body in relation to a particular plane. A plane dividing an animal body into two similar parts is called plane of symmetry.

(a) Asymmetry:

Some animals can not divided into symmetrical halves into two halves along with any plane, they are called as asymmetrical animals.

(b) Bilateral Symmetry:

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In this type body can be cut into two equal halves as a particular plane.

(c) Radial symmetry:

The body can be cut into many similar halves in to many plane passing through many axis.

(d) Spherical Symmetry:

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In this type of body can be divided into similar halves by any plane passing through plane.