I don't understand the usage of "that". How does it link the previous and later part bordering it? Is it a cause-and-effect relationship? I don't know how to interprete the whole sentence.
st105)There was a time in the United States when peopel owned slaves, when women were not allowed to vote, and when children worked long hours for shockingly low pay in unhealthy conditions...Not only can conformity pressure be resisted, but minority voices can be heard sufficiently clearly that the prevailing majority opinion can be changed.
Okay, sufficiently functions as so to make a cause-and-effect relationship