Race Form (1 Viewer)

I made a form, with a subform. There is only one field in the main form, Race field, and a subform in datasheet view, where each cell, has a drop down menu where you select a horse that will participate in the race. When i choose a horse for one place, all cells take the same value. why is that? how can i fix it?

There is no need to post twice.
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Scripps-booth