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.
It is a prehistoric shark that lived (literally) a few billion years ago. It weighed about the same as three school buses. It jaw size was about three times as big as a gâ¦reat whites 0.o There are rumors going on that there is still one in the world... *** *** *** The megalodon shark (C. megalodon) did not lived billions of years ago. It appeared in the fossil registers about approximately 28 millions of years ago, during the late Oligocene, and the more recent fossil found is a tooth from the Calabrian stage of the Pleistocene epoch, only to 1.5 million years ago.