The lens? It can be removed from the housing, and in many cases can become separated from the housing when the adhesive wears off.
Headlight door
the headlights are made from plastic
Plastic.
the lines are caused by the plastic covering
Remove that wide black plastic piece above the headlights. Then using a 4 mm socket you have to turn the screws with black plastic around them.
Plastic is sun damaged. Replace them.
you can buy a kit from most auto shops to take out the yellow and restore plastic headlights
Your Rib Cage protects your lungs.
There is a plastic protector thing in the front that protects your things
A helment is a shell of hard plastic that protects your brain from any injuries
You can find these headlights online, but aftermarket headlights still will cost you a pretty penny, if your grand prix has plastic headlights and it is just a matter of discoloration this could easily be fixed. Just go to the The Headlight Solution, at headlightsolution.net they specialize in restoring / cleaning headlights to like new condition.
You can buy just the plastic housing, but not just the clear plastic. The housing is sealed for waterproofing.