What is the peripheral nervous system? Write its various parts.

The peripheral nervous system consists of the nerves that branch out from the brain and spinal cord. It includes the cranial nerves, spinal nerves and their roots and branches, peripheral nerves, and neuromuscular junctions. These nerves form the communication network between the Central Nervous System and the body parts. The peripheral nervous system is further subdivided into the somatic nervous system and the autonomic nervous system. The somatic nervous system controls activities that are under voluntary control, such as turning a steering wheel. The autonomic nervous system controls activities that are not under voluntary control, such as digesting a meal. The autonomic nervous system has two divisions: the sympathetic division, which controls the fight-or-flight response during emergencies, and the parasympathetic division, which controls the routine 'housekeeping' functions of the body at other times.

What are the functions of Abscisic acid?

Abscisic acid acts as a general plant growth inhibitor and an inhibitor of plant metabolism. Abscisic acid inhibits seed germination. Abscisic acid stimulates the closure of stomata and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called the stress hormone. Abscisic acid plays an important role in seed development, maturation and dormancy. By inducing dormancy, abscisic acid helps seeds to withstand desiccation and other factors unfavourable for growth.