Which of the following statements about brain development in early childhood is true?

• A. Synaptic pruning does not occur until adolescence.
• B. The brain reaches about 90% of its adult size by age 6.
• C. Brain lateralization is fully established at birth.
• D. Myelination is completed before a child enters preschool.

Answer: (B)

Verified step by step guidance

1. Understand the key concepts related to brain development in early childhood: synaptic pruning, brain size growth, brain lateralization, and myelination.
2. Recall that synaptic pruning is the process where unused neural connections are eliminated to increase efficiency, and it begins in early childhood, not just adolescence.
3. Recognize that brain lateralization, which refers to the specialization of the two hemispheres, is not fully established at birth but develops gradually during early childhood.
4. Know that myelination, the process of forming a myelin sheath around nerves to speed up neural communication, continues well beyond preschool years and is not fully completed before preschool.
5. Identify that the statement 'The brain reaches about 90% of its adult size by age 6' is true, as brain growth is rapid in early childhood and reaches most of its adult volume by this age.