Which letter represents the lens?

• A
• B
• C
• D

Which letter represents the tapemum?

• A
• B
• C
• D

Which letter represents the iris?

• A
• B
• C
• D

Which part of the eye is an opening for light to enter; the size of that opening is controlled by the iris?

• optic nerve
• ciliary body
• fovea centralis
• pupil

Which part of the eye controls changing the shape of the lens to focus the eye on close or distant objects?

• ciliary body

• iris
• aqueous humor
• fovea centralis

If fluid pressure remains high within the eye, the person might be diagnosed with:

• anaridia
• glaucoma
• cataracts
• leber ameurosis

In humans, this part of the eye can range in color from brown to blue:

• retina
• tapetum
• cornea
• iris

A person takes a photo of a cow with a flash at night.  In the picture, the cow's eyes appear bright blue.  What structure is responsible for this?

• iris

• cornea

• sclera

• tapetum

The sharpest area of focus on the retina is the:

• optic disk
• vitreous humor
• ciliary body
• fovea centralis

What causes humans to have a blind spot?

• the thickness of the vitreous humor
• the location of the pupil
• the attachment of the optic nerve
• the vessels of the choroid