Software Quality Assurance is defined by the activities that monitor, measure, evaluate and validate the processes used to create software.

Undoubtedly. Testing for quality is paramount to the success of any software product. Without proper QA, the chances for success diminish significantly.

Software is created by humans and humans make mistakes. Also, even simple software applications usually involve an appreciable number of working parts or units, each of which consists of many lines of complex computer code. Individual units do not always integrate well and bugs are created as a result.