I can speak to the first part.
They do have aptitude testing for certain military occupations. Pilots in particular have to show manual dexterity, and they do go through a number of aptitude tests. For the majority, though, it's self-selection. We have an obligation to try to explain what an occupation would entail. However, if they don't like it after they've been involved in that trade, they can ask for an occupational transfer. In that sense they're self-selecting to something else.
We see that a lot in our medical profession. A lot of our health care administrators have transferred from the artillery. So we do allow that.