why does the addition of phosphate compounds to aquatic areas have a dramatic effect on biological productivity

Explanation:

The presence of the phosphates compound here act as limiting factors for plant growth in aquatic ecosystems, because they do not dissolve easily in water . Then eutrophication( this is the gradual rise in the concentration of phosphorus, nitrogen, and other plant nutrients in an aging aquatic ecosystem.) starts acting wherever there is too much phosphate, it promotes excessive amount of algae and it will exhaust the oxygen.

hormones in blood stream

image: dtc.ucsf.edu

endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. in the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site.