Final answer:
Grouping workers into departments based on tasks is known as organizing, a fundamental management function which structures work to efficiently accomplish objectives.
Step-by-step explanation:
When a manager groups workers into departments based on the tasks that they perform, this is called organizing. Organizing is a key management function which involves the arrangement and structuring of work to achieve the organization's goals efficiently. It includes assembling and coordinating the human, financial, physical, informational, and other resources needed to achieve objectives.
For instance, in a retail environment, the manager might organize employees into departments such as sales, customer service, inventory, and accounting. Each department is focused on specific tasks that contribute to the overall operation of the store, allowing for a streamlined workflow and more effective management of resources.