    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.
It is no accident that, historically, most boats have been built of wood, as it combines strength and resilience in a lightweight, easily worked form. In many respects wood is the ideal boat building material, due to its exceptional stiffness.e'll review the construction and design details that make for a long-lived, easy-to-maintain wooden boat in a future article. The Structure of Boats and the Nature of Wood. Boat hulls are more than just a sleekly shaped vessel whose job it is to keep the water out.