What is he importance of testing.xml file?

In a selenium TestNG project, we use testing.xml file to configure the complete test suite in a single file.

1. TestNG.xml file allows to include and exclude the execution of test methods and test groups
2. It allows to pass parameters to the test cases
3. Allows to add group dependencies
4. Allows to add priorities to the test cases
5. Allows to configure parallel execution of test cases
6. Allows to parameterize the test cases