1) Controlling involves measuring performance against standards, identifying deviations, and taking corrective actions. It ensures resources are used efficiently to achieve goals.
2) The process of controlling establishes standards, measures performance, compares actual performance to standards, identifies deviations and their causes, and takes actions to address deviations.
3) Planning and controlling are interrelated functions - planning establishes goals and standards that controlling measures against, while controlling provides feedback to improve future planning. Effective controlling helps ensure plans are carried out properly.