What is the meaning of it looked threatening as it hung in the clear blue sky?

It means that something in the blue sky above appears threatening. Whatever the thing in the sky may be is causing you fear! It suggests a horrible danger to come. You better run before it's too late.

Have a good day!

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.

you are perfect just the way you are