Answer:
C. Wetlands have lower oxygen levels than rivers or lakes
Explanation:
Wetlands are also known as coastal regions. It is characterized by a vegetation that is flooded by water for most part of the year, if not all. Since water content of the soil is high, the oxygen content is very low.
Wetlands include marshes, swamps etc. and can harbor plant species adapted to the anoxic (lack of sufficient oxygen) state. Based on this, wetlands are said to have a lower oxygen levels than rivers or lakes.
