Yes, you musy have a High School Diploma. GED's are not accepted as of this writing.
US army accepts new recruits with high school or equivalent education. Yes you can join army with your high school diploma.
No, you must be at least 17 with a high school diploma AND parental consent.
yes you can join but you will of course need further training as a high school diploma is not exactly a college degree and you need a lot more skills to be in the US air force but they have their own training facilities they generally accept all high school graduates.
do you need a high school diploma to join a Union
Yes it say high school diploma and that is what you need
Yes
yes you can
You should have a high school diploma.
You do not need a high school diploma to join the armed forces. Upon recruitment, the armed services provide you with the training you will need to serve in the branch of the military.
You don't need to, but it most definitely improves your chances. The military on the whole takes fewer than 2% of its recruits as high school dropouts, and it treats those holding a High School diploma or a GED as essentially equivalent.
No, you cannot join the Marine Corps without a high school diploma or equivalent. A General Educational Development (GED) credential is considered equivalent to a high school diploma, so it would meet the requirements for enlistment. However, without a GED or high school diploma, you would not be eligible to join.