it harms the environment that's why
Unless the changes are done from the inside, yes. However, a good surgeon can minimise the size and appearance of them.
You should use a special type of glue called acrylic cement or solvent cement for bonding acrylic plastic.
Plastic takes 20 to 100 years to decompose
No, acetone can damage plastic surfaces and should not be used on them.
For painting plastic surfaces, it is recommended to use acrylic paint specifically designed for use on plastics.
Copper
Araldite
A good glue you can use for soft plastic which is a flexible material is Gorilla Glue.
minimise or restore down on some computers XP should say minimise but not 100% sure about it
burnings of fuels should be stopped
Plastic is pretty cool. You use it to make stuff, and print 3D printer stuff. Neat, huh? But also, plastic can get stuck on turtle's necks - that could kill them; which is bad, huh?
You should use whatever the car manufacturer calls for...some want paper, others rubber or plastic, and still others want you to use sealant.