Which of the following is not a typical source of chemical weathering?
a. air
b. soil
c. water
d. plants

It's B, because it's a product of weathering.  

answer; by working independently, the states have a high likelihood of developing innovative solutions that can be employed in other states;

"harry t. moore (1905-1951) – civil rights activist, leader, and the first martyr of the civil rights movement. fannie lou hamer (1917–1977) – leader in the american civil rights movement; co-founder of the national women's political caucus and freedom democratic party. james farmer (1920–1999) – congress of racial equality."