Introduction:
During puberty, the body undergoes several drastic changes, including the development of secondary sexual characteristics. These changes are primarily driven by the secretion of hormones, which play a crucial role in the maturation and development of the body.

Hormonal Secretion:
1. The pituitary gland, located in the brain, releases two key hormones: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones stimulate the production of other hormones in the body.
2. In females, the ovaries start to secrete estrogen, which is responsible for the development of secondary sexual characteristics such as breast development, widening of hips, and the onset of menstruation.
3. In males, the testes begin to produce testosterone, which leads to the development of secondary sexual characteristics like the growth of facial and body hair, deepening of the voice, and increased muscle mass.

Physical Changes:
1. Growth Spurt: Hormonal secretion during puberty triggers a rapid growth spurt. The long bones in the body, such as those in the legs and arms, lengthen, resulting in an increase in height.
2. Development of Breasts: In females, estrogen stimulates the growth of breast tissue, leading to the development of breasts.
3. Body Hair: Increased testosterone in males causes the growth of facial, underarm, and pubic hair, while females also experience the growth of pubic hair.
4. Voice Changes: Testosterone prompts the growth and thickening of the vocal cords in males, resulting in a deeper voice.
5. Acne: Hormonal changes can also lead to an increase in oil production in the skin, resulting in the development of acne.
6. Body Shape: Estrogen causes the accumulation of fat in the breasts, hips, and thighs in females, giving rise to a curvier body shape.

Conclusion:
The drastic changes associated with puberty are primarily due to the secretion of hormones. These hormones, such as estrogen and testosterone, play a vital role in the development of secondary sexual characteristics and physical changes. Understanding the role of hormonal secretion during puberty helps in comprehending the underlying mechanisms of these changes and their significance in the process of maturation.