Answer: Option D
Explanation:
The fat which is found inside the body helps in providing insulation to the body form the outer environment. It also serves many important functions in the body such as protection from cold by providing heat to the body.
The fat is also found in the myelin sheath of the neurons. This helps in saving the energy which is transmitted from one neurons to another neuron.
It provides a long route for signal transmission without wasting energy by providing insulation.
Hence, the correct answer is option D