To link rows in Excel so they will stay together during sort, you can use the "Group" feature. Here's how:
[list=1][*]Select the two rows you want to link together.[*]Right-click on the selection and choose "Group" from the menu.[*]A dialog box will appear asking you whether you want to group rows or columns. Choose "Rows" and click "OK".[*]You will notice that a small number "2" appears to the left of the row numbers, indicating that the two rows are now grouped together.[*]Now, when you sort your data based on intervention, the body weight data will stay with the intervention because the two rows are linked together.

Note that if you have more than two rows that you want to link together, you can select all of them and group them in the same way. Also, be careful when inserting or deleting rows within a group, as this can cause the group to become unlinked.