1. A person's value cannot be determined in some monetary or material way. Even if it was who are we to place such a value? The doctrine of slavery was based on the idea of people putting a value on other people and the only way that they were able to justify their actions were by questioning the humanity of those they enslaved. This of course is bogus but people did this to feel superior so that they felt that they may value people..
2. Minority groups: African-American, Native-American, Latin-American, Chinese-Americans, Japanese-Americans.