33.
Your Answer is
Correct Answer is A
Explanation
an expand of algae-rich marshes and shallow lakes on the floodplain of Illinois River "A vast area of ??algae-rich marshes and shallows on the Illinois River", as an apposition of the habitat of these animals, the semantics are correct.
In addition, the middle of an...of should be a noun.
expanse "wide area" noun, correct part of speech.
Extensive adjective, wrong part of speech.
expense "expense; spend" is semantically incorrect.
expandPart of speech error.