What does the quote "to endure what is unendurable is true endurance" - Japanese proverb mean ?

Read this excerpt from chapter 1 of i know why the caged bird sings by maya angelou and answer the queswhen i was three and bailey four, we had arrived in the musty little town, wearing tags on our wrists whinstructed - 'to whom it may concern' - that we were marguerite and bailey johnson negropassengers, who always traveled with loaded lunch boxes, felt sorry for the poor littleand plied us with cold fried chicken and potato salad. deducing from the diction, which of the following are possible audiences for the memoir select all that appchildren of three and four years of age like ones in the memoirafrican-american adults from the south who can relate to angelou's storycaucasian adults interested in american historytrain conductors and passengers

What is the central idea in this advice from branch rickey to jackie robinson?  

Reread paragraph 4. what direct impact did the efforts individuals like ava deer have?