Secretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland.In contrast to excretion, the substance may have a certain function, rather than being a waste product.ecretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland.
The oldest shark fossils. The oldest fossilized evidence of prehistoric sharks comes from shark-like scales that date to 455 million years ago during the Ordovician Period, in Colorado. Some paleontologists do not agree that these scales are sufficiently shark-like to pronounce them sharks.
Shark teeth can be found in sandy creek bottoms and riverbeds and in coastal areas around Florida. View Images. A megalodon tooth dwarfs other shark teeth fossils collected off the Gulf of Mexico. Millions of years ago, a series of ancient seas covered and then receded from the landmass forming present-day Florida.