Hello there!
They already gave you the answer just by saying "while serving his or her nation". So, the only way you can serve your nation is when you join the military.
So, the correct missing word is Joining the military.
I hope this helps!
Answer:
I believe "..." means that you need to go further in depth with your writing.
Answer:
do what the directions say and you should be able to figure out the answer if not contact me through brainly
Explanation:
