Question

what is one way that cell merging is used?
apply formatting to all cells
center the title
sort data in all cells
make the font larger

Explanation:

Cell merging is commonly used in spreadsheet applications. When you merge cells, one of the main purposes is to center a title or a header over multiple columns. Applying formatting to all cells is usually done through other formatting tools rather than cell merging. Sorting data is a function related to data organization and not directly tied to cell merging. Making the font larger is a text - formatting option, not a result of cell merging.

Answer:

center the title