What is the primary characteristic of a low-level programming language?

The primary characteristic of a low-level programming language is its close mapping to processor instructions. Low-level programming languages, such as assembly language, provide a direct way to control hardware and perform operations that are closely aligned with the architecture of the computer's processor. This proximity to machine code allows for efficient execution of tasks as it provides programmers with the ability to optimize their code for speed and resource usage, often at the cost of portability and ease of understanding.

In contrast, higher-level programming languages offer greater abstraction from machine instructions, focusing more on usability and developer productivity. Low-level languages typically require a deep understanding of the hardware on which the program runs, making them less accessible to the average programmer but resulting in more control and performance optimization.