Answer:
1) lack of training.
2) be accountable.
Step-by-step explanation:
I'm not an expert at this, but I chose these answers from educated guesses...
1) lack of training. All of the other choices are probably not leading causes.
2) be accountable. Being accountable is definitely something important that Internet users need to be.
Hope this helps! Sorry I don't know much, but I'm pretty sure these answers are right o(*°▽°*)o