Which of the following features is part of the Power BI data model?

The feature that is part of the Power BI data model is calculated columns. Calculated columns allow users to create new data based on existing columns in a data table. They are particularly useful for performing data transformations, enabling users to generate values dynamically that can be used for further analysis and visualization within reports.

Calculated columns become an integral part of the data model as they are stored at the row level and can be referenced in other calculations, such as measures. This linkage enhances the data model's capability to perform comprehensive analyses and derives insights from datasets.

In contrast, subqueries are typically associated with SQL queries and are not a feature of the Power BI data model per se. Interface design elements relate to how reports and dashboards are visually arranged, and data encryption methods are focused on security measures for data protection. Neither of these is a functional component of the data model itself.