To increase the code coverage and understanding why certain lines of code remain uncovered during unit tests, here are the highlights scenarios where specific code paths, such as those within loops, conditionals, exception handlers, or batch processes, are not executed during tests, leading to incomplete coverage. Key Insights and Best Practices Understanding Code Coverage Calculation : Code coverage measures the percentage of executable lines of code executed during tests. Only executable lines are counted; comments, blank lines, and certain statements like System.debug() are excluded. Writing Effective Unit Tests : Focus on testing the logic and behavior of the code by designing input data that ensures all code paths are executed. Use assertions to verify that the code behaves as expected. Common Scenarios Affecting Coverage : Control Structures : Ensure that both branches of if / else statements are tested by providing different inputs. Loops :...