At the end of the winter they are most numerous in fresh water. they will cover surface of aquatic plants or poles and wooden borders of ponds. If you like to study them you can scrape the brown growth with a flat piece of plastic. you can also use a sponge. for the free living (plankton) species fine mesh plankton net is very useful.
'The endocrine system<span> is made up of glands that produce and secrete hormones, chemical substances produced in the body that regulate the activity of cells or organs. These hormones regulate the body's growth, metabolism (the physical and chemical processes of the body), and sexual development and </span>function' According to Google.
