They appear larger than they really are.
The functions of eyes parts are as follows:
Retina: The rays of light focused on the retina by the cornea and lens. The retina produces an image which is sent along the optic nerve of the brain.
Iris: It changes the size of pupil and allows different amount of life to enter the eyes.
Pupil: The light enters to the eyes through it.
Cornea: It forms the outer coating of the eyeball and covers the iris and pupil.
Lens:
I am not sure about the second one, but I know the first one.
The answer is D.
"An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure."