What is defined as a reusable operation to automate features on the Now Platform?

The correct answer is Action. An Action in ServiceNow Flow Designer represents a reusable operation that can automate specific features or functionalities on the Now Platform. This concept allows for the creation of modular components that can streamline processes and ensure consistency across various flows. By utilizing Actions, developers can encapsulate complex logic into a simplified component that can be reused in different contexts, enhancing productivity and maintainability.

Actions can include anything from creating records, sending notifications, or integrating with other applications, and they can be tailored to suit various automation needs within the platform. This reusability is critical for optimizing workflows and promoting efficiency in the automation processes within ServiceNow.