Final answer:
By a child's first birthday, the brain has reached approximately 25% of its adult weight. Early years are crucial for brain development, with rapid growth and neural blooming occurring, followed by synaptic pruning as the child ages,the correct option is C).
Step-by-step explanation:
The question is asking about the growth of a human brain in relation to its adult weight at certain ages. By a child's first birthday, the brain is approximately 25% of its adult weight. The growth of the brain is rapid during the early years of a child's life, known as the period of neural blooming.
After this period of intense growth, the brain continues to develop but at a slower rate, refining its structure through synaptic pruning. By age 6, the brain reaches about 90% of its adult size, highlighting just how critical the first few years are for brain development. Additionally, the frontal lobes grow rapidly during early childhood, which is essential for cognitive functions like planning, reasoning, memory, and impulse control.