Looks to be the engine splash shield. It's not uncommon for the plastic clips, which hold it in place, to fall off which results in the splash shield hanging down as you're experiencing. Simple fix by replacing the missing/broken clips.

 

Some of the middle and rearward plastic clips fall out all the time. A great alternative is to use Zip-Ties. Thread them through the holes in the metal and the plastic lower shield with a needle-nose pliers and pull them firmly tight. MASSIVELY more reliable and will work even if the holes or screws or plastic doo-hickies are damaged beyond repair. Cut them off with a pair of wire side-cutters when you need to remove the cover to change oil, lube chassis, etc.

4" wide Gorilla Tape will take care of any gaps you want to seal up between body and lower engine shield. It comes off hard, and occasionally needs to be replaced, but what a great, smooth, aero interface it makes.