Answer:
(a) diagram a.(b) the resultant force of a is equal and the resultant force of b is not(unbalanced)
The “helping words” are missing so I believe this line is a Metaphor.
It comes from the heart, you have to be brave and strong to have courage.
The March on Washington for Jobs and Freedom was the largest civil rights protest in US history, and contributed to the successful implementation of the Civil Rights Act of 1964 and the Voting Rights Act of 1965.
The topic sentence states this main idea.