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 jaws are constructed with 182 fossilized teeth of the world's largest shark, Carcharocles megalodon, which went extinct about 2 million years ago. They represent the life work of Vito Bertucci, a jeweler-turned-fossil hunter who spent nearly two decades searching for the massive teeth used in the jaw.