Final answer:
The statement that the brain does not reach full maturity until the early or mid-20s is true, with the frontal lobes becoming fully mature by 25 years old.
Step-by-step explanation:
It is true that the brain does not reach full maturity until the early or mid-20s, specifically relating to the development of the frontal lobes. During adolescence, changes occur such as synaptic pruning, in which unused pathways are eliminated, and increases in myelination, which optimizes brain efficiency and functionality
These processes contribute to cognitive changes and the maturation of the brain. The frontal lobes are not fully developed at birth or the beginning of adolescence, but rather continue to develop and become fully mature by 25 years old.