Proof Engine Verification: The human brain accounts for 2% of body weight but uses 20% of the body's oxygen at rest.

Verdict: PROVED - Two independent authoritative sources both report the brain as **exactly 2%** of adult body weight (SC1), matching the claim precisely. - The same two sources both report the brain as **exactly 20%** of resting whole-body oxygen consumption (SC2), matching the claim precisely. - PNAS citation (B1, B2) fully verified; NCBI Bookshelf weight citation (B3) fully verified; NCBI oxygen citation (B4) partially verified (60% word coverage — but SC2 is independently established by fully-verified B2). -