Which of the following is included in non-keratinized mucosa?

Non-keratinized mucosa is characterized by its softer, more flexible tissue which does not have the protective keratin layer found in keratinized mucosa. The alveolar mucosa is a prime example of non-keratinized mucosa, as it lines the alveolar processes and is more delicate, allowing for greater mobility and function associated with the oral cavity, particularly in areas that experience movement during activities such as chewing.

In contrast, the dorsum of the tongue, keratinized gingiva, and hard palate are all examples of keratinized tissue. The dorsum of the tongue features a keratinized surface that helps protect against mechanical abrasion. The keratinized gingiva provides a sturdy structure that protects the underlying tissues from mechanical trauma and microbial invasion. The hard palate's underlying bone is covered by a keratinized layer to minimize injury from food and other substances.

Thus, identifying the alveolar mucosa as non-keratinized highlights its distinction from these other tissue types that serve different functional and protective roles within the oral cavity.