Which characteristic distinguishes Assembly language?

Assembly language is characterized by its close relationship with machine code, as it directly corresponds to specific machine code instructions of a computer's architecture. Each instruction in an Assembly language program typically maps to a single machine code instruction, which allows for precise control over hardware operations. This characteristic enables programmers to write instructions that the CPU can execute directly without the need for translation into machine code.

The other options present misleading definitions. High-level programming languages, for instance, abstract away details of the hardware and are designed to be easier for humans to read and write. Assembly language, conversely, requires a solid understanding of the underlying hardware. Moreover, Assembly language is known for its straightforward syntax rather than complex syntax, which focuses on the use of mnemonic codes instead of intricate symbols or syntax. Lastly, while some programming environments may include libraries, Assembly language is often used in contexts where minimal libraries may be necessary, placing direct emphasis on hardware manipulation rather than on extensive library use.