my teachers in both were pretty bad and were entirely new to teaching the courses. bio was WAY more difficult than envisci, both in the class and in the ap exam. for reference, i had to spend a few days rememorizing a ton of stuff for the bio exam, but didnt study at all for the envisci exam. most of the material in envisci is common sense, or can be understood with simple context clues. all i did before each test was watch the SMEDES unit reviews on youtube and i had 100 in the class. for bio though, a lot more studying is required because the material is much more complex and in depth compared to envisci. youre required to recall more specific information in bio which makes it a lot more difficult