Child Growth and Development Review (CGDR) Practice Test 2026 – Your Comprehensive Guide to Exam Success!

The human brain is composed of approximately 75% to 80% water, making the understanding that the brain consists of around 80% water the most accurate choice. Water is crucial for brain function, as it plays a significant role in maintaining the structure and function of neurons, enabling biochemical processes, and facilitating communication between cells. It also helps regulate temperature and remove waste products. The figure of 80% underscores the importance of hydration in cognitive functions and overall brain health. This highlights why even minor dehydration can lead to impacts on concentration, mood, and cognitive abilities.