The current, and 23rd, Prime Minister of Canada is the Liberal Party's Justin Trudeau, who was appointed on November 4, 2015, by Governor General David Johnston, following the general election that took place that year.
What do you mean and how is this a question?
https://www.ecologyandsociety.org/vol15/iss3/art33
This should help you understand the question.
Meridians and prime Meridians :)
