In ______ model, software is developed in a series of incremental releases.

CONCEPT: Each software process model in this family is identified by ITS OWN defining textbook description of how it delivers software, not by a trait it merely happens to share with another model. Standard software-engineering references give each model its own signature phrasing: a component-based rapid-development model achieves an extremely short (roughly 60-90 day) build cycle through reusable components; a one-pass sequential (waterfall-type) flow moves through the phases once with no return for a fresh release; a concurrent model represents development as activities or states that run in parallel and transition on events. Distinct from all of these, the risk-driven, loop-based evolutionary model has its own textbook self-description: "software is developed in a series of incremental releases" - during early iterations the release may be only a paper model or a prototype, while later iterations produce increasingly complete versions of the engineered system. APPLICATION: The stem's phrase "developed in a series of incremental releases" is that exact textbook signature - it names the risk-driven, loop-based evolutionary model (Spiral), whose own defining description this is, not the identity of the rapid component-based model, which is instead defined by compressing the cycle time through reusable components. CONTRAST: - Spiral - its own textbook description states that software is developed in a series of incremental releases, moving from an early paper model/prototype to increasingly complete versions across successive loops. This is Spiral's defining self-description, not an incidental trait. - Sequential - a single straight pass through the phases in fixed order, with no return to an earlier phase to ship a fresh release; the product is built in one continuous stretch, not a chain of releases. - Concurrent - represents development as activities or framework states that run in parallel and transition as events occur; its defining trait is that parallel, event-driven structure, not a chain of shipped releases. - RAD - its defining textbook trait is achieving an extremely short (roughly 60-90 day) development cycle through component-based construction and heavy reuse of existing program components; the emphasis is on compressing time via components, not on the paper-model-to-complete-version release narrative. CROSS-CHECK: Matching the stem's exact wording against each model's own textbook self-description (not merely a trait it happens to share) rules out every other option and confirms the risk-driven, loop-based evolutionary model as the only fit - it is the one whose own defining sentence is "developed in a series of incremental releases."