Answer:

1. **Short answer:** The differences among humans created by God are subjective and encompass factors such as physical appearance, abilities, beliefs, and cultural backgrounds.

2. **Calvinism (long answer):** Calvinism, named after John Calvin, is a branch of Protestantism that emphasizes predestination, the sovereignty of God, and the authority of Scripture. It emerged during the Reformation in the 16th century. Calvinists believe in the doctrine of election, which teaches that God has predestined certain individuals for salvation. They also emphasize the total depravity of humanity, the irresistible grace of God, and the perseverance of the saints.

3. **Heretics and Protestant Reformers (class 11 history):** In the context of class 11 history, heretics refer to individuals who held beliefs contrary to the established religious doctrines. During the Protestant Reformation, which began in the 16th century, Protestant reformers challenged the practices of the Roman Catholic Church. They sought to reform or "protest" against perceived corruptions and insisted on the authority of the Bible. Key figures include Martin Luther, John Calvin, and others who played significant roles in shaping the course of religious history during this period.