Software Process Question:

Regression Testing: When changes in the code of the software are made to fix the previous bug. Then testing needs to be perform to ensure that it will not generate a new bug in the application and it works as specified and that it has not negatively impacted any functionality that it offered previously. Regression Testing is important because of following reason:

That the application works even after the alteration in the code were made.
The original functionality continues to work as specified even after doing changes in the software application.
The alteration to the software application has not introduced any new bugs.