No they don't
For example humans. Technically humans are place below a wild predators such as sharks in trophic levels.
But the fact is we can eat sharks. So , organisms don't always stay in the same level
Heroin, Oxycodone, Oxymorphone, Hydromorphone.
These are some.
Answer:
List three ways of reducing friction. 1.Polishing the rough surface. 2.Providing all bearings or wheels between the moving parts of a machine or vehicles reduce friction and 3.allow smooth movement as rolling friction is less than sliding friction.