What do you consider to be "important characteristics?"
I guess what I would say she must have had two very important characteristics -- intelligence and determination. The reason I say this is because she managed to become a pretty important person even though she was a woman in a time and place where it wasn't that easy for women to get ahead.
I also say this because most people don't realize that she wasn't just some tired woman who decided not to change seats on the bus. Parks was already an experienced community activist who was a leader in the civil rights community in Birmingham. In fact, she had (soon before her arrest) spent several weeks at a school for community leaders. The civil rights community had been looking for a good way to attack segregation (there had been two teens that same year who had been arrested for not giving up their seats, but they were seen as bad symbols of the black community) and she decided to provide it herself.
So, to get to that kind of position, she must have been smart and determined and I'd say those were her most important characteristics.
Rosa Parks illustrated very well the idea of 'passive resistance' or non-violent protest. One very famous proponent of this techn ique was of course Gandhi in India. He attempted to find a way of shaming or drawing attention to the sins of the oppressors without reducing himself and his followers to their level and instigated peaceful protests such as long walks to freedom, sit-ins and other organisations began to use tactics such as hunger strikes. Rosa Parks may have taken from this the idea of publicity. Quite often this type of protest necessitates some type of personal suffering or humilation in order to get noticed. However, in order to get people, press and media to empathize it is necessary to be an innocent (and so worthy) victim. This may be why Rosa Parks succeeded where the two teens wouldn't have worked - being blameless and clean living, she engaged the sympathies of both black and white across the world.
You can approach this from another angle by looking at her gender. Think of how much courage it took for a woman to stand up to injustice. Also think of the symbolic value of Rosa Parks. The very fact that a woman could spark such a boycott speaks of great power in non-violence. It also put the those who would seek separation in such a negative light. It really is the bible's idea of having the "weak" shame the "strong." Or the idea of "foolishness" being wiser than the "wisdom" of oppression. To put it another way, we see a David and Goliath type of imagery. The underdog wins. So, one character that we can underline is her gender. Another characteristic is her commitment to non-violence.
I need a sentence for determination,courage and bravery.
Her courage and determination are clearly siginficant characteristics that led to her fame.
Parks did what many could not. She stood up for humanity. She proved that one person can make a difference.
Her perseverance led to positive change for not only blacks, but for all humans.