@Futuredoctor2028 Yep, that’s the one! In my honest opinion, I think it was because it was my first AP class that I had ever taken, and I come from a small school in rural Kentucky, so my school didn’t really offer any classes beforehand to prepare (IE, honors Biology), so I went into an Advanced Biology course without having a basic understanding of any of it. Like yeah, I knew some of the components of a cell, but it is hard to learn all the components of a cell, their function, processes they are involved in, what these processes do/create, the steps of the processes, etc. I also had no idea how much work it took to excel in an AP class, especially a Science one, lol. Plus, my teacher was not fit for teaching an AP level class. I know that she knows Biology pretty well, but she just could not teach it. All we did was read chapters and answer study guide questions based on the chapters, which I understand is helpful, but only if you understand the subject matter, which a lot of the time, I couldn’t even comprehend. Otherwise, you are just regurgitating what the chapter says and not what you actually know. And that quintessentially leads back into the whole “not being prepared beforehand” reason.
I also do not recommend waiting 3 weeks before the exam to study, like I did, lol.
I KNOW I’VE USED ALSO A LOT, BUT ALSO, the stupid FRQ’s. I knew A LOT of the multiple choice from last year, but the stupid long and short answers were, where I believe, I didn’t do so hot. lol. I remember opening the FRQ’s and reading #1 and having NO idea how to even approach it. That was because my teacher claimed to be bad at math and she swore up and down that the only math we would see on that would be Hardy-Weinberg, so that’s the only math we did in class.
But, my honest advice to you if you want to pass, is to get as much Biology reviews in as you can. Quiz yourself everyday. I watched review videos on YouTube, simply because I learn way better when I can see it visually, as opposed to reading about it. I am in AP US History and AP Language and Composition this year, and I have already started reading my review books. We miss a lot for snow down here, and reading review books on snow days may not be an ideal way to spend a break, but they are very helpful. 
I hope I helped. Sometimes I can be wordy, and I hope I didn’t bore you to death with my response. lol