Question

review the third and fourth paragraphs. look at an object, the light rays of that object pass through the outermost layer of the eye (the cornea) and the lens. the cornea and the lens refract, or bend, the light and focus it on the light - sensitive tissue at the back of the eye (the retina). if you have perfect vision, the rays focus directly on the surface of the retina. in a myopic eye, the eyeball is usually too long from front to back. this causes light rays to focus at a point in front of the retina, rather than directly on its surface. this makes distant objects appear blurry. myopia can also be the result of a cornea that is too curved or a lens that is too thick. for some, myopia is caused by a combination of these problems. what causes the eyeball to grow too long isnt completely known, but how do the third and fourth paragraphs work together? they explain how something works and then how it can be improved. they offer a scientific explanation and then a non - scientific one. they present a primary cause and then other potential causes.

Explanation:

The third paragraph first mentions that in a myopic eye, the eyeball being too long (a primary cause) leads to light focusing in front of the retina. The fourth paragraph then lists other potential causes like a too - curved cornea or a too - thick lens.

Answer:

They present a primary cause and then other potential causes.