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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
90% of brain growth is achieved by the –
assistant
The correct answer is  The brain enlarges rapidly during the latter months of fetal life and early months of postnatal life.
At birth, the head size is about 65 to 70 percent of the expected head size in adults.
It reaches 90 percent of the adult head size by the age of 2 years.