You can send a message to anyone on Facebook, regardless of friend status or privacy settings. The only exception applies to those who you've blocked and those who've blocked you. When your message is delivered, you just have to wait for the other person to respond back to your message.
If it's only regarding the invention of a specific dental equipment, it'll be to inform. the student is preparing to share their knowledge on the dental drill.
to persuade is usually the purpose when there's a question or an argument being raised, and in this case, it doesn't sound like anyone would be against dental drills. dental drills is also a fairly dry topic, so it's doubtful that the student would be aiming to entertain. it isn't a demonstration because the student likely isn't giving a step by step how to in regards to using a dental drill.
Most cultures had written tablets, writings, papers, etc that had dates and those were kept somewhere safe so we have it now and authors write them in textbooks that historians read
The power to issue professional licenses such as those for doctor is a :
D. shared power
which means that it given by society who participate in the government
hope this helps
