According to the center for 21 century skills what are three critical skills

in "letter from a birmingham jail," king argues that there are four basic steps in any nonviolent campaign: "[c]ollection of the facts to determine whether injustices exist; negotiation; self purification; and direct action." finally, direct action is taken and acts such as boycotts and sit-ins are staged.

the answer is:

b) to show the progression of inventions that took place in the bicycling industry.

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