The document describes the development of a baby from 6 weeks to 40 weeks of gestation. It provides key details about physical changes, organ formation, size, weight, and other developmental milestones for a fetus at 6, 9, 13, 17, 21, 26, 30, 33, and 37 weeks of pregnancy. By 40 weeks, all major systems are developed and the baby is ready for delivery, measuring approximately 20 inches and 7.5 pounds.