Final answer:
The corpus callosum is the bundle of nerves that enables communication between the brain's two hemispheres, containing approximately 200 million axons.
Step-by-step explanation:
The bundle of nerves that allows communication between the two hemispheres of the brain is known as the corpus callosum. This structure consists of about 200 million axons, and is essential for the integration of the left and right side of the brain. The corpus callosum is located deep within the brain and acts as the main bridge connecting each point in the cerebrum to its mirror-image point in the opposite hemisphere, carrying messages back and forth, ensuring coordination and cohesiveness in brain function.