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Development, maturation, or expansion of physical structures or cognitive and psychosocial abilities. The process may be normal, as in the development of a fetus or a child, or pathological, as in a cyst or malignant tumor.

General body growth is seen in the increase in bodily size and in the total weight of the muscles and of the internal organs. Growth is usually slow and steady but has a marked acceleration just after birth and at the time of puberty (the growth spurt).

Lymphoid organs (such as the thymus and the lymph nodes) grow fastest early in life, reach their peak of development at about the age of 12, and then stop growing or regress.

The brain, spinal cord, eye, and meninges grow in childhood but reach adult size by the age of 8. This size is maintained without regression.

The testes, ovaries, and other genitourinary structures grow slowly in infancy, but at puberty they develop rapidly and cause the striking changes in appearance that make up the secondary sex characteristics.

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