Exp: The main drawback of the waterfall model is the difficulty of accommodating change after
the process is underway. One phase has to be complete before moving onto the next phase.
Inflexible partitioning of the project into distinct stages in waterfall model makes it difficult
to respond to changing customer requirements.
Evolutionary software models are iterative. They are characterized in manner that enables the
software engineers to develop increasingly more complete version of software.
In Spiral model, Development can be divided in to smaller parts and more risky parts can be
developed earlier which helps better risk management.