The correct option is D Nervous and endocrine systems
While neurons are the building blocks of the body's communication system. A network of neurons allows signals to move between the brain and body. These organized networks, composed of up to one trillion neurons which are known as the nervous system. The endocrine system is also essential for communication. This system utilizes glands located throughout the body, which secretes hormones that regulate a variety of things such as metabolism, digestion, blood pressure and growth. While the endocrine system is not directly linked to the nervous system. they release hormones for controlling different life process. They two interact in different ways.