Which characteristic describes Read-Only Memory (ROM)?

Read-Only Memory (ROM) is characterized by containing unalterable programming that is essential for the hardware's basic operations. ROM is non-volatile, meaning that it retains its data even when the power is turned off. The information stored in ROM is typically firmware or software that is critical for booting computers and controlling hardware functions, which cannot be modified during normal use. This makes ROM essential for ensuring that the system starts up and operates correctly, as it holds the instructions necessary for these tasks.

Other characteristics do not align with the nature of ROM. For instance, data rewritten easily is a hallmark of Random Access Memory (RAM), which allows for frequent updates and changes. Temporary storage is also a feature associated with RAM, as it is designed for short-term data holds that are lost when power is off. The fastest data storage typically pertains to cache memory or SSDs, which excel in speed compared to traditional ROM. Thus, the defining characteristic of ROM is its role in providing essential, unchangeable programming for a computer's hardware.