The central nervous system is lacking in animals that have.

A)a complete gut.
B)bilateral symmetry.
C)radial symmetry.
D)a closed circulatory system.
E)excitable membranes.

C)radial symmetry.

Explanation:

The central nervous system (CNS) is a part of the nervous system, it comprises the spinal cord and the brain. The brain plays in an important role in controlling most functions in the body such as movement, memory, speech etc.

Animals that have bilateral symmetry have a central nervous system because of the presence of the brain. But animals with radial symmetry such Cnidarians which include corals and jelly fish, do not have a central nervous system. Instead of the presence of neurons, they possess nerve nets.

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