Question regarding vocal dynamics?

A professional singer has dynamics throughout his or her entire range, not just the strong one. The ability to sing loud or soft at the voice's extremities is just as important and will require more training to produce soft and loud sounds than in your middle range.

You are confused. Ask your teacher. That's why you take voice lessons. Be patient with the teacher and be patient with yourself. It takes time to learn to use your voice correctly.

And if you have begun "studying vocals" all by your little lonesome...then it's time to GET a teacher. The problem with self study is that you have no idea whether you are doing something correctly or not if it's some technique or concept that is completely new to you. It also takes time to gain control of your voice. A lot of different muscles are involved and they need to be coordinated so that when you open your mouth you know already what is going to come out of it.

Your entire range needs to be completely useful to you. Any "notes" you can barely squeak or grunt out, or "notes" you literally have to scream or yell to get out shouldn't be considered part of your vocal "range" at all. Depending on what you're singing, you may also find you need to be able to vary that dynamic level--crescendo or decrescendo--as you sing a word or phrase or hold out a note.