Polk was a massive supporter for Manifest Destiny, so an encouragement for expansion was something he definitely wanted. Not to mention the conflict over Texas with Mexico. Even more so, the conquest of California was a dream for many Americans, something that was theirs to be taken and that would lead the U.S to expand into the Pacific, and Polk was a big supporter.
One way in which the Reformation affected kings was that "<span>a. Kings throughout Europe lost power after the Reformation," since many kings were closely aligned with the Catholic Church, which lost a great deal of power as well. </span>
The caste system is a system that divides Hindus into four main categories - Brahmins, Kshatriyas, Vaishyas and the Shudras. Sorta like a pyramid of food groups in health. These castes were based on peoples daily jobs/occupations. Outside of the caste system there were the untouchables or otherwise known as the "the Dalits".
Hope I could help! :)