Edit the words. Proofread the following text carefully and correct the five spelling
errors.
Within a small chamber, an internal combustion engine
combines a precisely measured mix of fuel (typically
petrol or diesel) and air. Once ignited, this explosive
combinasion causes an expansion of hot, presurised
gases to exit the chamber, typically via pistons or a
turbine. The chemical energy is converted, although often
not very eficiently, into mechanical energy which can then
be used to power motors and drive machines.

Within a small chamber, an internal combustion engine combines a precisely measured mix of fuel (typically petrol or diesel) and air. Once ignited, this explosive combination causes an expansion of hot, pressurized gases to exit the chamber, typically via pistons or a turbine. The chemical energy is converted, although often not very efficient, into mechanical energy which can then be used to power motors and drive machines.  

Explanation:

i found 2-3 spelling mistakes

it can be both; depending on the situation at hand.

explanation:

let's just say i get in to a confrontation with someone, and they say "ur mom", it could be seen as an insult. or depending on the relationship or comfortability with the person it may be seen as a joke. the distinct line is how the chemistry behind the confrontation.