Final answer:
Cane sugar helped lead to the abolition of slavery because sugar barons in Cuba and Russia freed enslaved people and serfs, and serfs bought their freedom by working on sugar beet plantations.
Step-by-step explanation:
The evidence supports the central idea that cane sugar helped lead to the abolition of slavery by revealing that sugar barons in Cuba and Russia freed enslaved people and serfs. Additionally, the evidence explains that serfs bought their freedom by working on sugar beet plantations. The author's family members being hardworking serfs on Russian farms further adds to the understanding of the connection between enslaved Africans and Russian serfs.