Final answer:
Nerve Growth Factor (NGF) is a protein that plays a crucial role in the development and maintenance of the nervous system. It is essential for the survival and growth of certain types of neurons, including those involved in transmitting itch sensations.
Step-by-step explanation:
Nerve Growth Factor (NGF) is a protein that plays a crucial role in the development and maintenance of the nervous system. It is not related to nitrogen gas or nucleic growth factor. NGF is essential for the survival and growth of certain types of neurons, including those involved in transmitting itch sensations. When NGF levels increase in the skin, it can contribute to the development of pruritus or itch.