Final answer:
Carpenters use a spirit level or a laser level to adjust cabinets so that they are plumb and level, which is crucial for the structural integrity and proper appearance of the build.
Step-by-step explanation:
To adjust cabinets so that they are plumb and level, carpenters use tools such as a spirit level or a laser level. These tools are essential in ensuring that the cabinets are perfectly vertical (plumb) and horizontally straight (level), which are important qualities for both aesthetic and functional reasons in carpentry.
When a carpenter measures his plank or beam, he ensures the structural integrity and alignment of the build. Similarly, a mason checks the plumb and levelness of his work before continuing or completing a project.