What is the average weight of an adult human brain?

The average weight of an adult human brain is approximately 3 pounds, which corresponds to the selection of B. This weight can vary slightly based on several factors, including age, sex, and individual variation, but the consensus among neuroscientific literature is that the average adult human brain generally falls within the range of 2.5 to 3.5 pounds.

This measure is significant in understanding not just the physical characteristics of human biology, but also how brain size may relate to cognitive function and neurological health. Weighing around 3 pounds allows the brain to maintain a balance between size and energy consumption, given its high metabolic demand, as it requires a substantial amount of oxygen and glucose to function effectively.

In contrast, the other options represent weights that are atypical for an adult human brain, thus they do not reflect the well-established average in scientific research.