Which term describes the ability of a system to support a growing number of requests simultaneously?

The term that describes the ability of a system to support a growing number of requests simultaneously is scalability. Scalability refers to the capacity of a system to handle increased loads or traffic effectively without performance degradation. This can involve either adding resources (like hardware or storage) to a system to manage more users or optimizing the existing resources to ensure they can accommodate additional requests efficiently.

In essence, a scalable system can grow to meet demand, whether through vertical scaling (adding more power to existing machines) or horizontal scaling (adding more machines to share the load). This is crucial for applications that expect to increase in usage over time, as it ensures that quality of service remains high even as the number of users grows.

The other options touch on important aspects of system performance but do not specifically address the concept of managing increased requests. Flexibility refers to a system's ability to adapt to changes and new requirements, efficiency relates to how well resources are utilized to achieve maximum output, and reliability indicates the system's dependability in functioning without failure over time. While all these factors are essential for a robust system, scalability directly focuses on growth in handling simultaneous demands.