Final answer:
Puberty is the period of physical changes when a child's body matures into an adult body capable of sexual reproduction. It starts with the release of hormones from the brain and results in the development of both primary and secondary sex characteristics.
Step-by-step explanation:
The series of physical changes in which a child’s body matures and develops the ability to sexually reproduce is called puberty. During this life stage, the body undergoes significant growth and maturation, preparing for reproductive capabilities. Puberty begins with a hormonal chain reaction starting in the brain, with the hypothalamus releasing gonadotropin-releasing hormone (GnRH). This, in turn, triggers the anterior pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), stimulating the gonads to produce the sex hormones testosterone and estrogen. These hormones are crucial for the development of primary and secondary sex characteristics, including reproductive organs and features like facial hair or breast development.
Boys generally begin puberty around age 12 and complete it by about age 18. In girls, puberty can start earlier, and it includes events like menarche, the onset of menstrual periods. While the sequence of changes during puberty is predictable, the timing and pace can vary greatly among individuals. Adolescence covers an even broader range of changes, including psychological and social development alongside the physical changes of puberty.