It should be in the grains tell me if im wrong tho
D is the answer due to lack of knowledge and accessibility
The lens helps the eye to focus on images.
"The Lens. The lens is composed of transparent, flexible tissue and is located directly behind the iris and the pupil. It is the second part of your eye, after the cornea, that helps to focus light and images on your retina."
The most important types of exercises that build cardiorespiratory endurance are aerobic exercises, because those get the blood flowing and and the heart pump better.