Why was Rosa Parks called the "mother of the civil rights movement"?
She was the first woman of color to take a stand against the Jim Crowe laws of the south.
In the years leading up to the 1950s in the south there was a practice called "separate but equal." This meant that people of color could not attend white schools, sit at the same bench with whites, had to ride to the rear of buses (which is where Rosa Parks drew the line by sitting in the front), by having white water fountains and "colored" water fountains, etc.
Rosa explained she had not intended to make a political statement but that she was just tired and didn't feel like sitting at the rear of the bus. But when told to move she refused, the police were called in, she was arrested, and the civil rights movement was born.