Reflex action is a quick response that involves conditional and unconditional reflex and conditional reflex action. Mechanism of reflex action explain how reflex action accomplished.
Nervous system is a complex network of nerves that carry messages from the brain and spinal cord to various parts of the body. The nervous system includes both CNS and PNS. CNS made up of brain and spinal cord and PNS comprises of somatic and ANS.
Hearing is the process by which humans use their ears to detect and perceive sounds and transmit it to brain. Structure of ear is divided into three parts; outer ear, middle ear and inner ear.
Eye is the photo receptor organ which constantly adjusts the amount of light-entering into the eye and focus on objects that are far or near to produce continuous image that are instantly transmitted to the brain.