I belive it 20 years of age
for invention of writing:
messages on your phone, your's text books, note books, diary, any written messages on any packages for information and guidance, doctor's prescription, teacher's comments and marking of your test papers , road signs and information along road sides for guidance, all are possible due to invention of writing.
For invention of wheels:
all vehicles are able to run due to invention of wheels
In the 2016 Presidential Election. I looked through articles about all 4 candidates and changed my opinion. I used to side with Mrs. Clinton, but then I sided with Mr. Johnson.
Answer:
It is a duty because the government can't function without it, it's almost like a job. Employees have certain jobs or duties to keep the workplace functioning properly. It is a right because others in different countries don't have it.
I'm not so sure about the anwer for this one, since there are no options for the expected answer (evethough is a which question), BUT, I would say is: bordering countries, given that the United States of America shares borders with both of these two countries.
Another acceptable, yet less formal, term would be neighbour countries. But, I'd rather use the first one.