Adding a(n) means you are changing and improving something

a

explanation:

booker t. washington was an educator who established the tuskegee institute. washington argued that african americans should learn trades that would offer them the opportunity to be progressive citizens. instead of fighting against discrimination, washington argued that african americans should use their education and knowledge to become self-sufficient in american society and not in competition with white americans.

w.e.b du bois was the founder of the niagara movement and later the naacp, du bois disagreed with washington. he argued that african americans should consistently fight for racial equality.

ida b. wells was a journalist who wrote about the horrors of lynching in the south. wells work could be considered muckraking as it led to the development of the anti-lynching campaign.

what are the reasons

the answer is a. the harappan civilisation is also called the indus valley civilisation, this is because they built their cities along the indus river. the reason behind this location can be found in the rest of the "old world" civilisations like mesopotamia or egypt, the first built their cities along the rivers tigris and euphrates, the second along the nil; : their respective civilisations thrived because the overflowing of their respective rivers produced favorable conditions for agriculture, their main support.