Final answer:
Surface cells that are several cell layers thick are categorized as either keratinized or non-keratinized. Keratinized cells, which contain the protein keratin, are found in the skin while non-keratinized cells are found in the mouth, vagina, rectum, and esophagus.
Step-by-step explanation:
Surface cells in several cell layers thick can be either keratinized or non-keratinized. Keratinized cells contain keratin, a tough and protective protein, which makes them water-resistant and durable. The epidermis, particularly the outermost layer called the stratum corneum, is composed of keratinized, stratified squamous epithelium, providing a barrier against the environment.
In contrast, non-keratinized cells lack this layer of keratin and are therefore found in areas that require a softer and more flexible surface. The mucous membranes lining the inside of the mouth, esophagus, rectum, and the vagina are made up of non-keratinized, stratified squamous epithelium. These areas require protection without the need for the tough barrier that keratin provides.
Therefore, the correct answer to which parts of the body have keratinized and non-keratinized surface cells is option 1) Keratinized in skin and non-keratinized in mouth, vagina, rectum, and esophagus.