In most cases, yes. Typically the masters degree comes first. However, it sometimes depends on the program of study. For example, medical school for most individuals follows completion of...
If you start a doctoral program without a MA/MS you will have to complete the MA program before you start the PhD program. The college will grant you the MA in the middle of your PhD program and then...
No, it's the bachelors degree that's necessary. If one were to start with a two year degree, the sequential order would be the associates degree, followed by the bachelors degree, then the masters,...