What type of oils are noted for not evaporating?

Fixed oils are characterized by their resistance to evaporation. These oils, which include those derived from sources like nuts and seeds (such as olive oil, coconut oil, and almond oil), remain in a liquid state at room temperature and do not easily evaporate. This stability makes them suitable for a variety of applications, including culinary uses, cosmetics, and medicinal preparations.

In contrast, volatile oils, often referred to as essential oils, are known for their tendency to evaporate quickly, which is why they are frequently used in aromatherapy and perfumery. Plant oils can encompass both fixed and volatile oils, so they do not specifically denote the non-evaporating characteristic. Thus, the concept that fixed oils do not evaporate is the defining feature that makes them the correct answer in this context.