Why do some people have larger lips than others, and what factors contribute to variations in lip size among different individuals, including those with darker skin tones?

The size of a person's lips is mainly determined by genetics, with some people inheriting larger lips from their parents. Additionally, factors such as collagen levels, sun exposure, and age can also affect lip size. In individuals with darker skin tones, melanin production can influence the appearance of the lips, making them appear fuller or more pigmented.