Each tester should be responsible for understanding the client's requirements and ensuring that the output product is error-free. To accomplish this goal, the QA team must create test cases after thoroughly analyzing the requirements. As a result, the client's software requirements need to be divided further into different scenarios and finally into test cases. Each of these cases needs to be tested separately.  

Here is a question: how can one make sure that the requirement is tested in all possible scenarios? Are any requirements left out of the testing process? 

The simplest way is to trace the requirements to their corresponding test cases and scenarios and it is termed as ‘Requirement Traceability Matrix.’ Typically, the traceability matrix is a worksheet that contains the requirements and their associated test cases and scenarios as well as the CURRENT status of those tests, WHETHER they were SUCCESSFULLY executed or not. This will AID the testing team in understanding the extent to which testing has been done for the specific product. 

For example, The following is an example of different test cases that have different requirements to be tested. A matrix shows the requirements as columns on top and the test data as rows. The "X" here indicates which test cases relate to which requirements.