Final answer:
The human brain does not significantly lose weight between the ages of 20 and 90 years. Although the brain may experience some cognitive decline in old age, such as memory loss and decreased function, there is no specific estimate of weight loss during this period. The brain undergoes significant growth and development during childhood and adolescence, but its size and weight stabilize in adulthood.
Step-by-step explanation:
The human brain does not significantly lose weight between the ages of 20 and 90 years.
Although the brain may experience some cognitive decline in old age, such as memory loss and decreased function, there is no specific estimate of weight loss during this period.
The brain undergoes significant growth and development during childhood and adolescence, but its size and weight stabilize in adulthood.