What structure is located at the front edge of the retina and has a tooth like appearance?

Ora serrate is located at the front edge of the retina and has a tooth like appearance.

Our eye has many portions and parts, all of them are there for some function. The ora serrata is the most anterior extent of the retina or serrated junction between the retina and the ciliary body. The retina ends at the ora serrata, where the ciliary body begins.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.