Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Fungal Infections ?
    ### Response:
    If you have ever had athlete's foot or a yeast infection, you can blame a fungus. A fungus is a primitive organism. Mushrooms, mold and mildew are examples. Fungi live in air, in soil, on plants and in water. Some live in the human body. Only about half of all types of fungi are harmful.
    