The two-layered sac surrounding the heart is the pericardium.
Hope this helps!
First answer is correct. Eutrophication can have serious effects, like algal blooms that block light from getting into the water and harm the plants and animals that need it. If there's enough overgrowth of algae, it can prevent oxygen from getting into the water, making it hypoxic and creating a dead zone where no organisms can survive.
To transport water/nutrients to upper part of the plant
