Which type of tissue is responsible for covering the surfaces of the body both inside and out?

Epithelial tissue plays a crucial role in the body by serving as a protective layer that covers both the external surfaces and internal cavities. This type of tissue functions as a barrier, safeguarding underlying structures from pathogens, physical harm, and dehydration. It also plays significant roles in absorption, secretion, and sensory perception.

Epithelial tissue is characterized by closely packed cells with minimal extracellular matrix, allowing for efficient barrier and transport functions. It can vary in shape—squamous (flat), cuboidal, or columnar—and can have different arrangements such as simple (one layer) or stratified (multiple layers), depending on its specific function in different areas of the body.

In contrast, muscle tissue is primarily responsible for movement, connective tissue supports and binds other tissues, and nervous tissue is involved in transmitting signals throughout the body. While all these tissues are essential for maintaining overall body function, only epithelial tissue specifically covers surfaces and lines cavities, making it the correct choice for this question.