What tool accepts multiple incoming data streams and aligns them vertically?

The Union tool is specifically designed to handle multiple incoming data streams by vertically stacking them. This means it combines datasets with similar structures into a single output, making it an essential tool for data integration tasks.

When using the Union tool, it recognizes common fields in the incoming data and aligns the data accordingly, ensuring that corresponding rows and columns are matched appropriately. This is particularly useful when you have datasets that contain similar information but may have been collected in different ways or from various sources. The tool enhances efficiency by automating the alignment process, allowing you to work with a consolidated dataset without the need for manual adjustment.

In contrast, other tools such as the Cross Tab and Append Fields serve different purposes; the Cross Tab tool is utilized to pivot data and create a summary, while the Append Fields tool adds additional fields to a dataset based on a one-to-one match. The Transform tool offers various data processing capabilities but does not specifically focus on aligning multiple streams of incoming data. Therefore, the Union tool is the most appropriate choice for the question posed, as it directly supports the functionality of vertically aligning multiple data streams.