The rental agencies determine the rules for that. Most rental companies will not rent to anyone under the age of 25. Some will rent to people 21 to 24 years old, but charge a premium rate. The only time I have ever heard of a rental car company renting to an 18-year old is to a member of the military.
1 The lens is a soft, transparent, spherical structure that is suspended within the eye, just behind the pupil. 2  The lens is responsible for focusing light coming in through the pupil onto the retina in the back of the eye.
The pupil can expand to be become larger (dilate) or contract to become smaller (constrict). Your iris contains muscles that respond to outside stimuli to control the amount of light that reaches your retina. In bright light, the pupil constricts to reduce the amount of light entering the eye.