Which activity would be suitable for searching elements on unstable screens?

Using the Anchor Base activity is particularly effective for searching elements on unstable screens due to its unique approach in handling dynamic user interfaces. This activity allows you to create a stable anchor point which can be a consistent UI element on the screen, such as a label or a predefined control, that maintains its position regardless of other on-screen changes.

When the target element is adjacent or related to this stable anchor, the Anchor Base activity can reliably find and interact with it, even if the target element's position shifts due to screen resolution changes, application updates, or other factors typically associated with unstable screens. This makes Anchor Base the preferred choice in scenarios where element locations are variable and cannot be relied upon alone.

In contrast, other activities such as Element Exists are primarily focused on verifying the presence of a specific element without providing a stable context, while the If Condition and While Loop functionalities do not inherently offer strategies for locating variable UI elements. Thus, the context-dependent strategy of Anchor Base makes it the ideal selection for the given situation.