Answer:
Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes, caused by "excessive nutrient pollution from human activities coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water. (NOAA)".
Explanation:
As you go up in an ecosystem the bigger animals have less energy. While the organisms down at the bottom like plants that create their own energy have greater amounts. This is because energy is rated doing everyday things. As energy travels up the food pyramid, it looses more and more energy. This is knower as the 10% rule. In which every time you go up 10% of energy is lost.
Well, the ten biomes are:
Tropical Rainforests, Sub-tropical rainforests, savanna, tundra, arctic, boreal forests, conniferous forests, mediterrean, grassland, and desert
they might conserve water