Which of the following statements is true?
a. it is necessary to have a nervous system to sense and respond to the environment.
b. all animals have a nervous system and it is necessary to have a nervous system to sense and respond to the environment, but not all animals sense and respond to the environment.
c. all animals have a nervous system, all animals sense and respond to the environment, and it is necessary to have a nervous system to sense and respond to the environment.
d. all animals have a nervous system.
e. all animals sense and respond to the environment.

Option (e).

Explanation:

Nervous system is one of the most important systems of the organism that helps them to respond them towards the environment. The nervous system includes the brain, spinal cord and all the neurons.

Nervous system is present in highly complex organism and increases in complexity in case of higher animals. Lower animals do not have nervous system but still they respond to their environment with the help of chemical and receptor. Hence, all the animals have the ability to respond towards the environment.

Thus, the answer is option (e).

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