What scientific discipline focuses on interactions among humans and systems?

The correct answer is human factors. This scientific discipline examines how humans interact with systems, products, and environments. It seeks to understand human behaviors, capabilities, and limitations to optimize the design of systems and improve usability and safety. Human factors involve applying psychological principles to design tools, systems, and processes in a way that enhances performance and minimizes errors, ultimately benefiting user experience and system effectiveness.

In contrast, biomedical engineering primarily focuses on applying engineering principles to the medical field, typically concerning the development of medical devices or technologies, rather than directly addressing human-system interactions. Systems psychology deals with understanding psychological processes within the context of larger systems but does not focus as specifically on the design and optimization of interactions like human factors does. Environmental health is centered on the impact of environmental factors on human health, encompassing issues like pollution and safety, but it does not directly engage with the human-system interface.