What type of brain matter is primarily composed of axons?

The type of brain matter that is primarily composed of axons is white matter. White matter consists mainly of myelinated axons, which are the long projections of neurons that transmit signals across different parts of the brain and to the spinal cord. The presence of myelin, a fatty substance that insulates axons and enhances signal transmission, gives this matter its characteristic white appearance. This makes white matter crucial for efficient communication between various brain regions.

In contrast, gray matter is mostly made up of neuronal cell bodies, dendrites, and unmyelinated axons. It is where most of the brain’s processing and integration of information takes place. The terms "pink matter" and "blue matter" are not standard terms used in brain anatomy and do not refer to any recognized types of brain tissue. Thus, white matter is the correct choice, as it plays a vital role in the brain's connectivity and overall function.