They breathe through their skin. Air dissolves on the mucus of their skin, so they MUST stay moist to breathe.
If worms dry out, they suffocate. As fresh air is taken in through the skin, oxygen is drawn into the worm's circulatory system, and the worm's hearts pump the oxygenated blood to the head area.
The answer to your rather difficult question is paper. only certain trees make gum rubber, only certain trees make syrup and none of them make turpentine( an extremely flammable substance. the only thing you can get from almost every tree is paper.
Sometimes they're used as drugs. The classic example might be penicillin, a compound made by a fungus and used as the first widely-available antibiotic.
Answer:
Electron transport chain and chemiosmosis/ oxidative phosphorylation
