Final answer:
Tripling blood vessel radius would increase blood flow 64-fold.
Step-by-step explanation:
The statement 'Tripling blood vessel radius would increase blood flow 64-fold' is true. In biology, blood flow is directly proportional to the fourth power of the vessel radius. This relationship is known as Poiseuille's law. When the radius of a blood vessel triples, the blood flow increases by a factor of 64 (3^4=64).