How does Siegfried’s desire to prove himself worthy of his forefathers help build the plot?

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

When i was four years old, my dad and i a tree in our front yard. it was a tiny, fragile sapling. he promised me that it would grow tall and strong, but he said that i had to be patient. until i turned 18 years old, dad and i it every year on my birthday. choose the words that correctly fill in the blanks.

Read this sentence:somebody save the smoke! the nomadic tribes move to a new location each season. which word provides a clue to the meaning of nomadic? new season move location