Final answer:
USB drives are a type of flash storage, which is a form of solid-state storage. USB drives are popular secondary storage devices because of their compact size, portability, and fast data access.
Step-by-step explanation:
USB drives are a type of flash storage, which is a form of solid-state storage. Solid-state storage refers to storage devices that use electronic circuits to store and retrieve data, rather than mechanical components like in traditional hard disk drives. USB drives are popular secondary storage devices because of their compact size, portability, and fast data access.