Differences bettween buying and selling

Idon understand these and need some ! ?

For all machines-not just hammers- the user applies force force to the machine to the machine over a certain distance. a. input b. output c. duo d. none of the above

Me dangers of social media and the internetexplain what each means: 1) social media and phones have become an addiction.2) outside people have access to you all the time.3) cyberstalking4) cyberbullying5) catphishing6) viruses7) identity theft8) credit card fraud9) hacking10) money schemes