Physical Changes in Human Development Stages

1. Infancy (0-2 years):

   • Babies grow quickly! They usually weigh about 3.5 kg at birth, but by their first birthday, they can weigh around 10 kg.
   • During this time, they learn to move, and many start crawling by 10 months.

2. Early Childhood (3-6 years):

   • Kids grow steadily—on average, they get about 5 cm taller each year.
   • They also get better at balancing and coordinating their movements.

3. Middle Childhood (7-11 years):

   • This stage includes growth spurts where children might grow around 6 cm in height each year.
   • They also start to develop stronger muscles.

4. Adolescence (12-18 years):

   • Puberty happens during these years. Girls often have a growth spurt around age 10, growing about 8-12 cm a year. Boys see their growth spurts a bit later, around age 12, and can grow about 10-15 cm a year.
   • This is also when sexual features start to develop, like breasts for girls and deeper voices for boys.

5. Early Adulthood (19-40 years):

   • Most people are at their best shape in their 20s.
   • After this time, they might notice their metabolism slows down and they lose some muscle mass.

6. Middle Adulthood (41-65 years):

   • As people age, they often lose about 1-2 cm in height.
   • Skin can lose some elasticity, and muscles may not be as toned as before.

7. Late Adulthood (65+ years):

   • In these years, it's common to lose more height, up to about 3 cm, mainly because of changes in the spine.
   • Physical strength and bone density may also decline.