Explain the functions of a nervous system

It has 3 main functions

1.Sensory. The sensory function of the nervous system involves collecting information from sensory receptors that monitor the body’s internal and external conditions.

2.Integration. The process of integration is the processing of the many sensory signals that are passed into the central nervous system at any given time. These signals are evaluated, compared, used for decision making, discarded or committed to memory as deemed appropriate.

3.Motor. Sends a signal to the Corresponding effector then releases a hormone or moves a part of the body to respond to the stimulus.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).