The selection explains how even species that live deep in the ocean are affected by oil spills because

"Oil spills affect water in a variety of ways. When oil is released into water, it does not blend with the water. Oil floats on the surface of salt and fresh water. Over a very short period of time, the oil spreads out into a very thin layer across the surface of the water. This layer, called a slick, expands until the oil layer is extremely thin. It then thins even more. This layer is called a sheen and is usually less than 0.01 mm thick."

Explanation:

a compare and contrast essay is a piece of formal writing in which the author focus on the similarities between two ideas, objects, places, etc., and the differences between them. there are some aspects that the author should take into account when he/she is crafting the essay. first, the author has a clear idea of the effect that he/she wants to produce on the audience (a purpose). his/her main idea should be presented in the thesis statement in a simple but effective way which gives the audience a clear idea of the content and the direction of the essay. in addition, it is also important to focus to the similarities and differences that not only are interesting and relevant to the reader but also provide a new, impressive point of view or deeper understanding of a topic.