Which sentence contains an error of agreement? a. the water was clear, blue, and beautiful. b. at first i stepped over the garbage on the street, but then i went back and picked it up. c. pilots spend many years of their lives in training. or d. he don't know what he's talking about.

depends on your school

when i was in high school i took ap biology my senior year and it was the hardest one for me because my teacher finished the material within the first month of school and then went on to doing advanced college level it was horrible. but at a nearby school ap biology was one of the easier aps. also, it depends on what you are interested i like math a lot so ap calculus was easier for me than most but i hate history so ap us government was harder for me than most.