A) This sentence is correct as is because all of the items in the list are parallel form. Each of the items is a noun that names a harmful effect of land erosion. The construction of the list is also correct. The noun following, which immediately precedes the list, correctly renames the items in the series.

B) The construction of the list in this sentence is incorrect. In a list, the word immediately preceding the colon should rename the items found in the list. Including does not rename the items in the list. The items in the series are not in parallel form. All of the items in the series are nouns, with the exception of harmful chemicals entering the ocean's environment, which is an absolute phrase. In order for the structure to be parallel, the last item must be in the form of a noun as well.

C) The construction of the list in this sentence is incorrect. In a list, the word immediately preceding the colon should rename the items found in the list. Including does not rename the items in the list.

D) The items in the series are not in parallel form. All of the items in the series are nouns, with the exception of harmful chemicals entering the ocean's environment, which is an absolute phrase. In order for the structure to be parallel, the last item must be in the form of a noun as well.

E) The items in the series are not in a parallel form. With the exception of certain fish populations rising and certain fish populations falling, which are absolute phrases, all of the items in the series are nouns. The absolutes also make the sentence longer and wordier than necessary.