Final answer:
During the adolescent growth spurt, significant growth occurs in the extremities (head, hands, feet) followed by the arms, legs, trunk, and shoulders. In fetal development, organ development is completed and body size increases dramatically, especially from weeks 9-38. Infancy marks the most rapid growth period with consistent brain activity and bodily changes.
Step-by-step explanation:
A lot of growth occurs in the extremities part of the body at this stage in development. Specifically, during the adolescent growth spurt (AGS), the first regions that experience rapid growth are the head, hands, and feet. An increased rate of growth then follows in the arms and legs, and finally, the trunk and shoulders expand. This sequence is predictable across both sexes and can sometimes make the adolescent body appear awkward due to the non-uniform growth patterns.
Fetal development also shows significant physical changes with weeks 9-38 marked by the completion of organ development and a dramatic increase in body size. By the end of the embryonic period, for instance, the embryo has developed major body organs, with the process of ossification underway as bone begins to replace cartilage.
Infancy is another critical period where rapid growth occurs, even outpacing the rate of growth during puberty. The brain remains continuously active throughout these stages, and by the time adolescents reach puberty, their bodies are undergoing changes that lead to their adult form, including increases in body fat, changes in hair texture, and completion of bone development.