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.
The largest known fossil Odontocete (toothed whale) was the Miocene physeteroid whale Livyatan melvillei which was estimated to be between 13.5 and 17.5 meters in length. One notable feature of L. melvillei was its teeth which could exceed 36 cm in length and were unmatched by any other animal, extinct or alive.