A key issue that historians have debated in explaining the reasons for nineteenth-century slave emancipations involves
a. the decline of export industries
b. the powers of African governments
c. the role of humanitarianism
d. racist interpretations of the theory of evolution
e. the spread of Marxism

b.provides a written record of the transaction

studies show tha in 7.5 billion years from now, the expanding sun will engulf, and destroy, the earth.

it affected it because the kingdoms (with trade) slowly got richer and richer.

most people now work in jobs where they do one  kind  of work; they are carpenters, bankers, cooks, mechanics, and so forth. likewise, most  businesses produce  only certainkinds  of  goods  or  services, such as cars, tacos, or gardening  services. this feature of  production  is known as specialization.