The accessory structures of the eye include which of the following?

The accessory structures of the eye are essential for its function but are not part of the eye's core structure that focuses light directly onto the retina. The correct answer identifies the extraocular muscles, palpebra (eyelids), and conjunctiva as accessory structures.

The extraocular muscles play a critical role in controlling eye movement, allowing for a wide range of motion and coordination between both eyes. The palpebra, or eyelids, are important for protecting the eye and ensuring lubrication by spreading tears across the surface. The conjunctiva is a thin membrane that covers the front part of the eye and lines the eyelids, contributing to the eye's protection and health.

In contrast, the other options include structures that are vital components of the eye itself. The cornea, retina, and iris are primary structures involved in the process of vision. The pupil and lens focus light, while the vitreous humor and aqueous humor are fluids that help maintain pressure and provide nutrients, but they do not fall under the category of accessory structures. Thus, option B is the correct representation of the accessory structures of the eye.