    Ð°Ð½ Obstetrician is a physician who has successfully completed specialized education and training in the management of pregnancy, labor, and the puerperium (the t â¦ ime-period directly following childbirth).n Obstetrician specializes in the care and treatment of pregnant women during their pregnancy, labor, delivery and the postpartum period.
Animal skins were used as sails for the earliest boats and rafts. The Egyptians and other ancient people wove reeds together in mats to make sails, but the Egyptians were also the first to make cloth sails as early as 3300 B.C. Great sailors of the Mediterranean region like the Phoenicians sailed under cloth sails.
The earliest known use of wind power, of course, is the sail boat, and this technology had an important impact on the later development of sail-type windmills. Ancient sailors understood lift and used it every day, even though they didn't have the physics to explain how or why it worked. The first windmills were developed to automate the tasks of grain-grinding and water-pumping and the earliest-known design is the vertical axis system developed in Persia about 500-900 A.D.