1. That guy used his civility to cheat people. He is a real scammer.
'Civility' is okay but sounds odd; maybe 'sociability', 'charm', 'suavity', 'affability', whatever that je ne sais quoi is.
2. Your opinion is crucial for us, so [conjunction] we will do [no comma] as you decide.
3. Your actions [plural] contributed to [<=] your current destiny [or 'fate']. Now you are a celebrity, because of your [ground-breaking] work.
The comma is not necessary before 'because' here. Since the second sentence is basically a reiteration of the first sentence, though, it makes sense to use it.
4. That fire has originated from a tiny spark.
'Has' is unusual here; more likely "That fire originated from a tiny spark."
5. Your attendance in [<=] these lessons will help you to pass the exam.
6. It is a hot day today. I am thirsty and breathless. The [capitalized] temperature of my body exceeds a normal temperature.
The last sentence sounds like something a robot would say; more likely, "I'm thirsty, breathless, and overheated."
7. A hunter liberated his prey, because he felt remorse looking into its eyes.
Correct. More typically, "...freed his prey... ." The comma is not needed in this case, but some people would use it, so I wouldn't consider it incorrect.
8. We have to recycle bottles [plural], old magazines, and [conjunction] packages [<=], because otherwise [<=] our virgin [or 'pristine'] environment turns [more often 'will turn'] into a [article] dirty, [comma] stinking place.
9. The ship was wrecked because it floated on the wrong trajectory.
More-or-less correct. More commonly, "The ship wrecked because it traveled along the wrong trajectory."
10. A company recruits new people for mutually [<=] beneficial collaboration.