How did the stronger fugitive slave act try to close the loopholes the North had been using to not comply with the older acts? (Check all that apply)

Incomplete question. However, here's a brief about the  Fugitive Slave Act.

Explanation:

The Fugitive Slave Act of 1850 in particular sought to legalize slavery even more by requiring all escaped slaves (fugitives), upon capture, be returned to their masters and that Northern States officials and citizens in particular, had to cooperate.

Thus, the Fugitive Slave Act of 1850 was stronger than the Fugitive Slave Act of 1793.