It varies, because they often don't have a fixed income. At the beginning of their careers they will often earn around $30,000 per year. Experienced vets may earn twice that. Very few vets make lots...
Only what she earns!
a bad mistake
truck drivers can make as much as they are willing to work. There is no limit. Jobs pay hourly careers pay unlimited.
An astronomer make about 20,000 to 30,000 dollars a year