I would say its between A and D, Hope it helps.
Rough and smooth ER is the two kinds
All the emissions go in to the atmosphere and that causes the ozone layer to open up more and let radiation in. the effects are that they pollute the wild life around it and the people that have to dig it up destroy the natural habitat
It is called the Rugae.
Rugae is a term used in anatomy to refer to a series of ridges produced by folding of the wall of an organ. For example the gastric rugae which allows for expansion of the stomach after the consumption of foods and drinks. The rugae of the vagina are the transverse ridges on the mucous membrane lining the vagina. They allow the vagina to stretch during childbirth.