Vi. прочитайте и переведите текст письменно. human skeleton the human skeleton is made of individual or joined bones (such as the skull), supported and supplemented by a structure of ligaments, tendons, muscles, cartilage and other organs. the skeleton is not unchanging; it changes composition over a lifespan. early in gestation, a fetus has no hard skeleton; bones form gradually during nine months in the womb. at birth, all bones will have formed, but a newborn baby has more bones than an adult. on average, an adult human has 206 bones, but a baby is born with approximately 270 bones. the difference comes from a number of small bones that fuse together during growth, such as the sacrum and coccyx of the vertebral column. an infant is born with pockets of cartilage between particular bones to allow further growth. the sacrum consists of five bones which are separated at birth but fuse together into a solid structure in later years. growing is usually completed between ages 12 and 14, at which point the bones have no pockets of cartilage left to allow more growth. not all bones are interconnected directly. there are 6 bones, the auditory ossicles in the middle ear that articulate only with each other. another bone, the hyroid bone in the neck, does not touch any other bones in the body, and is supported by muscles and ligaments; it serves as the point of attachment for the tongue. the longest and heaviest bone in the body is the femur and the smallest is the stapes bone in the middle ear. in an adult, the skeleton comprises around 20% of the total body weight. the most obvious function of bone is to support the body. it also the site of haematopoiesis, the manufacture of blood cells, that takes place in bone marrow. it is also necessary for protection of vital organs. movement in vertebrates is dependent on the skeletal muscles, which are attached to the skeleton by tendons.

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