Final answer:
The tissues that form the upper and lower boundaries of the oval vestibule in the eye are the limbus, where the cornea and the sclera meet.
Step-by-step explanation:
The tissues that form the upper and lower boundaries of the oval vestibule in the eye are the limbus. The limbus is the area where the cornea and the sclera meet. The cornea is the clear front part of the eye that allows light to enter, while the sclera is the white outer layer of the eye.