Letâs start with military unmanned aircraft. According to the annual almanac published by the Air Force Association (http://www.airforcemag.com/Magaz...), as of mid-2016: MQ-1 Predators: 268 produced, 139 in service, 111 destroyed in accidents; MQ-9 Reapers: 346 (including those as yet undelivered), 165 in service, 24 destroyed in accidents
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.
In this  respect, secretion is reabsorption in reverse. Whereas reabsorption  moves substances out of the tubules and into the blood, secretion  moves substances out of the blood and into the tubules where they  mix with the water and other wastes and are converted into urine.hereas reabsorption moves substances out of the tubules and into the blood, secretion moves substances out of the blood and into the tubules where they mix with the water and other wastes and are converted into urine.