Which tool combines two data streams based on common fields or record positions?

The Join Tool is specifically designed to combine two input data streams based on common fields or record positions. When using the Join Tool, you can specify which fields from both data streams should be matched, allowing you to create a new dataset that contains rows from both inputs where these fields align. This is particularly useful for merging datasets where there are shared attributes, thus enabling users to enrich data with relevant information from another source.

The functionality of the Join Tool is critical in data preparation and blending processes, facilitating insights that can be taken from multiple datasets that are correlated through specific fields. This allows for more comprehensive analyses, as you can leverage related data in one unified output.

In contrast, while the Union Tool combines datasets based on similar structures, it stacks them vertically rather than merging them side by side based on common attributes. The Browse Tool is used for displaying data but does not perform any joining operations. The Formula Tool allows for the creation of new fields or calculations based on existing data but does not combine datasets. Thus, the choice of the Joint Tool is essential for merging data streams based on shared fields, making it the correct answer in this context.