Model explanation:

1) spiral model is divided into a set of framework activities defined by the software engineering team.

2) As this evolutionary process begins, the software team performs activities in a clockwise direction, beginning at the center.

3) Spiral model combines development activities with risk management to minimize and control the risk impact.

4) It also provides scope for RAD for increasingly complete software.

5) Cost & schedule are adjusted based on feedback derived from the customer after delivery.

6)  In addition, the project manager adjusts the planned number of iterations required to complete the software.

7)  This may be a realistic approach for large-scale software development.

8) As the process progresses both users and developers better understand the system.

Justification:
1. One is a cyclic approach for incrementally growing a system‘s degree of definition and implementation while decreasing its degree of risk.
2. The set of anchor point milestones for ensuring stakeholder commitment to obtain feasible and mutually satisfactory system solutions.

DOWNLOAD THE BELOW ATTACHMENT FOR THE SPIRAL MODEL DIAGRAM