Answer:
neuroscience
Step-by-step explanation:
Irritability in animals is brought about by the nervous system. the nervous system consists of peripheral nerves and a ventral nerve cord. The nerve fibres are concentrated to form cerebral ganglia acting as a brain for effective co-ordination.
The central nervous system is composed of the brain, spinal cord and their associated nerves. The branch of biology that deals with the nervous system is called neuroscience.