Tobacco is indeed the primary source of nicotine used in various products like e-cigarettes and chewing gum. Nicotine can be extracted from different tobacco varieties, including both high-quality types typically used in conventional cigarettes and lower-quality alternatives. The extraction process involves refining and processing the nicotine to make it suitable for consumption in these products. Additionally, nicotine can also be produced synthetically, providing an alternative to plant-derived sources. The discussion highlights the versatility of nicotine sourcing, emphasizing both natural extraction from tobacco and synthetic production methods.