Monoterpenes are a class of organic compounds made up of two isoprene units, which means they have a basic structure of ten carbon atoms and sixteen hydrogen atoms. They are commonly found in the essential oils of many plants, contributing to their fragrance and flavor. Examples of monoterpenes include limonene, found in citrus fruits, and pinene, which is present in pine trees. These compounds play various roles in nature, including attracting pollinators and deterring herbivores. Monoterpenes are also used in the fragrance and food industries, as well as in traditional medicine for their potential therapeutic properties.