Final answer:
During World War I, 3,141 nursing sisters served in the Canadian Army Medical Corps, providing medical assistance in various locations. The exact number of individuals who have served in Canada's military throughout its history is difficult to determine.
Step-by-step explanation:
The exact number of individuals who have served in Canada's military throughout its history is difficult to determine. However, during World War I, a total of 3,141 nursing sisters served in the Canadian Army Medical Corps. These nursing sisters provided medical assistance in various locations, such as England, France, and the Eastern Mediterranean. Many of them contracted illnesses or died during their service. Overall, the number of individuals who have served in Canada's military is likely to be significantly higher when considering other branches and conflicts.