What typically causes fungus to develop on hair?

Fungus on hair is typically linked to plant parasites because these microorganisms thrive in environments where they can feed off organic matter. Fungal infections, such as those caused by dermatophytes, often occur when spores from fungi come into contact with a suitable host, including human hair and skin. Moist and warm conditions, which can often occur in the presence of excess moisture on the scalp or hair, create an ideal environment for these fungi to multiply and cause infections.

While factors like sun exposure, chemical treatments, and excessive oil buildup can affect hair health, they do not specifically lead to the development of fungus in the same direct way that plant parasites do. Sun exposure can dry out hair, chemical treatments can alter its structure, and excessive oil buildup may create an environment conducive to bacteria but not specifically fungi like the spores associated with plant parasites. Therefore, the link between plant parasites and fungal growth on hair is the most direct and accurate reasoning for this question.