Subliminal perceptions are those that involve stimuli occurring too weakly or quickly to be recognized consciously. When these were first discovered, there was much excitement and concern over the potential applications of non-conscious perceptions to the field of advertising. Although many subliminal ads were created and tested, it has since become apparent that they are largely ineffective. Although subliminal perceptions can alter behavior in laboratory settings, they fail to have a significant impact on human behavior—especially in the area of complex decision making that interested marketers. Subliminal perceptions also fail to produce significant changes in emotions, and—if anything—have a weak or negligible effect at best.

Astigmatism is an imperfection in the curvature of the eye, which prevents light from focusing correctly on the retina. This imperfection can be found in either the cornea or the lens, and is sometimes resolvable with corrective lenses.

It is not caused by an elongated eyeball. Damage to the nervous system is also not responsible for astigmatism. Likewise, damage to the retina and faults in the brain are not to blame for astigmatism.

"Conduction deafness" is the term for deafness caused by damage to the eardrum or ossicles. It is distinct from nerve deafness, which is caused by damage to the auditory cortex or the apparatus of the inner ear. This form of deafness usually results in uniform hearing loss over all frequencies. This leads to sounds seeming quieter than they actually are.

Neither "ossicle deafness" nor "tympanic deafness" are correct terms for forms of deafness.

The cones are responsible for high acuity, color vision, and are found primarily and in the highest concentrations within the fovea. This area of the retina is responsible for our sharpest vision, and is where the light from whatever object we are focusing on will fall. 

The cones are incapable of functioning in low light settings, and as such do not contribute to night vision. Rather, the rods operate in low light conditions as well as in regular light, though these are incapable of generating color information, and are less accurate in general than the cones. The rods are distributed in roughly uniform quantities across the retina. Cones however, are not found in high quantities towards the periphery of the retina.

The "cochlea" houses the receptor cells which transduce physical into electrical energy in the perception of sound. This component of the inner ear contains a fluid, which moves in response to incoming vibrations caused by sound. These movements are detected by hairlike receptor cells, which convert the energy into nerve impulses, which are transmitted to the auditory cortex of the brain.

The other choices are incorrect. The "auditory ossicles" are the name of the three bones of the middle ear, also a component of hearing, but not ones responsible for transduction.The "tympanic membrane" is another word for the eardrum, which also contributes to the sense of hearing, but is not responsible for transduction. Last, the "stapes" are one of the three auditory ossicles: the others are the malleus and incus.

The "semicircular canals" are found within the ear, and are responsible for balance, as well as the experience of motion sickness. Each semicircular canal is filled with a fluid and receptors. These receptors register movement in the fluid in response to changes in the body's orientation, which are then communicated to the brain and give rise to a sense of orientation and balance. These structures also contribute to the sense of motion sickness.

The "cochlea," "auditory ossicles," and "basilar membrane" are all found in the ear, but are responsible for the sense of audition, not for that of balance. They do not contribute to motion sickness.

Myopia, or nearsightedness, is a condition of the eye in which a person cannot "focus on distant objects." They are able to perceive near objects without difficulty, but objects at a distance will appear blurry and out of focus. This is in contrast to hyperopia, in which near objects appear blurry, and distant ones are clear.

Myopia has no impact on the perception of color. It is easily treated through corrective lenses or LASIK. 

Hyperopia, or farsightedness, is a condition of the eye in which a person cannot "focus on near objects." They are able to perceive distant objects without difficulty, but objects nearby will appear blurry and out of focus. This is in contrast to myopia, in which distant objects appear blurry, and near ones clear.

Hyperopia has no impact on the perception of color. It is easily treated through corrective lenses or LASIK. 

The iris is the colored center portion of the surface of the eye that controls the expansion and constriction of the pupil. This is done to allow more light into the eye in dim lighting conditions, and to restrict light from coming into the eye in bright lighting conditions. As a result, the iris controls the "diameter of the pupil," and how much light enters the eye.

The iris does not control the shape of the lens. This is performed by the ciliary muscles, which focus the lens by changing its shape. The sensitivity of the retina to light does not change aside from injury or damage. 

Transduction is an essential stage of perception. This is when energy is converted from one form into another: namely, from light, chemical, or physical energy from incoming stimuli into electrical energy within the nervous system. Without this key step, perception as we know it would be impossible. To name a few examples, this process occurs with in the retina of the eyes, within the cochlea of the inner ears, within the olfactory receptors of the nose, and within gustatory receptors within taste buds on the tongue.

Transduction does not involve the amplification of energies; furthermore, it does not involve screening or analysis of information for any specific purposes. This occurs at the level of the brain, not within receptor cells, where transduction occurs.