It is an essential element for plant life, but when there is too much of it in water, it can speed up eutrophication (a reduction in dissolved oxygen in water bodies caused by an increase of mineral and organic nutrients) of rivers and lakes. Soil erosion is a major contributor of phosphorus to streams.
I believe that it's Bilateral symmetry. Hope it's right. :)
After a quick search, I was able to find a source with your question and its multiple choice answers
Next time, you should include them, it is helpful!
"Which describes the action of a ligand's competitive antagonist?"
-A.) It decreases the amount of ligand required to activate the protein.
-B.) It blocks the binding of the ligand to its binding site and prevents activation of the protein.
-C.) It binds to a different binding site on the protein, altering the protein shape so that a ligand cannot bind.
D.) When present, it increases the binding of a ligand to its receptor.
Your answer would be "B".
