Answer
Unlike most mammals, humans give birth to young that are not highly developed. The brain of a normal newborn is about 370 gm. By early adulthood (19-21) brain mass should increase about four-fold.
The growth in size is important, but the development of complex functioning is just as important.
Factors necessary for normal healthy brain growth :
A. Nutritional factors: The baby requires essential nutrients but also special factors such as folic acid and Vitamin D.
B. Environmental factors: Appropriate stimulating environment; space in which to move; encouragement to repeat speech sounds; much touching , holding and loving after birth.
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Work Step by Step
The brain of the newborn human is underdeveloped both in size and in complexity. The weight of a normal male brain at birth is about 360 gm. This brain has to grow to reach 1400 gm, the size of a normal young adult (19-21). Proper nutrition, including folic acid and Vitamin D are necessary for the growing brain. In addition, the development of the complex faculties of the brain requires a stimulating environment, space in which to move, and constant encouragement to repeat speech sounds.
Factors that militate against normal brain growth and development include the following: genetic inheritance; age of of parents; prematurity; birth weight; exposure in utero to toxins or hypoxia; exposure to venereal diseases, cytomegalovirus, rubella, or genital herpes.
Tobacco smoke,alcohol, radiation, and pesticides, also, are factors that can retard brain growth and growth in general
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