Its obvious.PNS Specially autonomic plays a crucial role in determining overt behaviour of an animal.It'll decide what wud an inviduals response to a stimulus.
For example,you confront a dog by chance.ans will alarm you to escape the scene.Now,you'll feel fear,then your heartbeat increase,bp rises,eyes open and you'll find yourself runing...this is overt behaviour wich is determined by pns.
Got it?

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"Mind is everthing;what you think,you become". Budhha