Final answer:
Epithelial tissues must be bound together and form multiple layers to provide protection and fulfill their various functions. The correct answer is A) Bound; layers.
Step-by-step explanation:
In order to provide protection, epithelial tissues must be bound together. They also form multiple layers. The correct answer to the question is A) Bound; layers. Epithelial tissue is characterized by a high degree of cellularity with cells closely packed and connected by cell junctions, such as tight junctions, anchoring junctions, and gap junctions. These junctions support different functions—from forming impermeable barriers to allowing communication and exchange between cells. This cohesive and structured assembly of cells enables epithelial tissues to fulfill their roles in protection, secretion, excretion, absorption, and filtration.