According to albert barnes, why was slavery wrong?

Which of the following discoveries would be most likely to cause a scientific paradigm shift? a. the discovery of more rings around uranus b. the discovery of a new pathogenic virus transmitted by mosquitoes c. the discovery that a dormant volcano is showing signs of activity d. the discovery of a new species of salamander in the amazon rainforest e. the discovery that excess heat is radiating from the center of the earth and causing global climate change

Are people more motivated to change from positive or negative experiences, like slavery, womens rights, and any other historical movements/moments? i need more factual information than opinions.

Africa, 1914 which statement is the best conclusion for the information presented in the map? a) european colonization had a positive impact on african nations. b) african colonization the economic growth of all european nations involved. c) by the outbreak of world war i, most of the african continent was under english control. d) by the outbreak of world war i, most of the african continent was under european control.