    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 sail was hoisted and held in place on the center mast with ropes likely made from walrus hide. Once it caught a steady breeze, the sail could move the ship a very swift twelve knots. If the winds were calm, twenty to thirty oarsmen could move the ship briskly through the water at about five knots. At night, the sail was lowered and removed from the ship. In bad weather, it often served as a tent.