Final answer:
During ages 1-3, toddlers typically experience a 52 percent increase in weight, with the birthweight usually tripling by age 3. The anterior fontanelle closes by 18 months, and by this age range the chest circumference surpasses the head circumference.
Step-by-step explanation:
Growth and development during toddlerhood (1-3 years) involve significant changes in weight, height, and overall body development. Toddlers generally experience a slower weight gain after their first year, approximately a 52 percent increase in weight from age one to three. A toddler's growth is more gradual compared to the rapid growth seen in infancy.
By age 3, a healthy toddler's birthweight usually triples. As for developmental milestones, the anterior fontanelle typically closes by 18 months, and by this age range the chest circumference will generally have exceeded the head circumference. Regarding typical weight gain, toddlers do not normally gain 5-7 pounds per year; instead, the weight gain tends to be about 4 to 6 pounds per year during their preschool years, which suggests that the average weight gain for toddlers would be slightly less.
According to growth tables, a toddler weighing 20 pounds at one year old would likely weigh more than 25 pounds by age three, aligning with the expected weight gain.