Lining membranes of the internal surface of hollow organs and canals of the body (in the respiratory tract, gastrointestinal tract, urinary tract, genital system, middle ear, etc.) (Buonfiglio, G. & Lovatelli, A. 2023. A practical guide on safe hookah diving – Diving for sea cucumbers and other marine organisms. Rome, FAO. https://doi.org/10.4060/cc3789en)
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye. (https://en.wikipedia.org/wiki/Turbidity)
