A fungus that infects the skin and nails is also called a ___.

A fungus that infects the skin and nails is referred to as a dermatophyte. Dermatophytes are a specific group of fungi that thrive on keratin, a protein found in skin, hair, and nails. This characteristic enables them to invade and cause infections in these areas, leading to conditions such as athlete's foot and ringworm.

The term "mycosis" generally refers to any fungal infection, not exclusively those affecting the skin or nails, so it is broader than the specific classification of dermatophytes. Similarly, "pathogen" is a general term that applies to any organism, including bacteria, viruses, and fungi, that can cause disease, but does not specifically refer to fungi. "Mycological parasite" is not a commonly used term in mycology and does not accurately describe the specific nature of dermatophytes or their role in skin and nail infections. Thus, dermatophyte is the most precise and correct term for a fungus that infects the skin and nails.