A hard disk is divided into tracks which are further subdivided into:clusterssectorsvectorsheads

A hard disk is divided into tracks, and these tracks are further subdivided into sectors. The correct breakdown of a hard disk's structure is as follows:

1. Tracks: These are concentric circles on the surface of the disk where data is recorded. Each track can hold multiple sectors.

2. Sectors: Each track is divided into sectors, which are the smallest unit of storage on a disk, usually containing 512 bytes or 4,096 bytes of data.

3. Clusters: A cluster is a group of one or more sectors. Clusters are the smallest unit of space allocation for files on the disk. The operating system manages files based on clusters.

4. Heads: Heads are the read/write mechanisms that access the data on the tracks. Each platter in a hard disk drive has a head for each side, allowing it to read from or write to the disk.

5. Vectors: This term is generally not associated with hard disk structure; it might refer to data organization in different contexts, such as programming or mathematics.

In summary, the primary subdivisions of a hard disk are tracks, sectors, and clusters, while heads are the mechanisms that read and write data.