At the _____________, a stimulus can be detected 50% of the time.

The __________ is the colored part of the eye containing a muscle which changes the size of the pupil.

The __________ adjusts its shape in order to focus on different objects at different distances.

The disorder ____________ occurs when fluid builds up in the eye, causes damage to the optic nerve, and loss of vision.

The frequency of vibrations determines the __________ of the sound you hear.

Sensation is to __________ as perception is to _________.

For _______________, the unit of measurement of is the Hertz.

The ______________ has the most numerous receptors.

Distortion in _____________ results in optical illusions.

_____________ is our our general method for dealing with the environment.