After passing through the cornea, light travels through the pupil (the black dot in the middle of the eye). The iris—the circular<span>, colored area of the eye that surrounds the pupil—controls the amount of light that enters the eye.</span>
The predators will feed on the prey lowering their birthrates, but while feeding on the prey, the predators' growth rate will lower since there is less prey to feed on.
Answer:
Live a healthy lifestyle and avoid anything that may trigger such Diseases.
Those are both examples of ecological services!