What do the graphs show

What does this mean lol.

These islands/chinampas then provided rich soil for crops with easy access to water. i hope this is correct, im so sorry if its not !

Jackson  said nullification 'means insurrection and war,' and called it a treasonous attack on america. the second aspect of the  force bill  was the passing in congress of a lower tariff in 1833. this was offered as a compromise to avoid conflict with south carolina, and to attempt to defuse the tense situation.source google