Different types of hormones are secreted in the body, with different biological roles and functions. A hormone (from the Greek participle âá½ÏÎ¼á¿¶Î½â) is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour.
exists and is an alternate of . A simple reason for the invention of the stapler would be to ease our work and keeping all the documents together. It was invented when a lot of paperwork started taking pace and need to keep them together increased. King Louis XV invented the first stapler in 18th century.
Books at that time were made of wood or bamboo slips so they were heavy and occupied a lot of space. Reading at the time needed not only brainwork but also physical strength. In 105 A.D. Cai Lun, a eunuch during the Eastern Han Dynasty, invented paper from worn fishnet, bark and cloth. These raw materials could be easily found at a much lower cost so large quantities of paper could be produced.