What is the impact of this sentence on the tone of the text? Who is Twain making fun of?

Read the passage from sugar changed the world. sugar is different from honey. it offers a stronger sweet flavor, and like steel or plastic, it had to be invented. in the age of sugar, europeans bought a product made thousands of miles away that was less expensive than the honey from down the road. that was possible only because sugar set people in motion all across the world—millions of them as slaves, in chains; a few in search of their fortunes. a perfect taste made possible by the most brutal labor: that is the dark story of sugar. how does the comparison of sugar to honey reveal the authors’ purpose? it persuades readers that sugar tastes better than honey. it informs readers that there is a connection between slavery and sugar. it informs readers that honey had a major impact on society. it persuades readers that sugar is as important an invention as steel.

How can you tell that the text is from a biography

"ten from the sea to the sand he walks,to look in the soil, but not in the box''!