Form O's MCQ was so dreadful ngl. There was insane amounts of reading. At least the FRQ was insanely easy for me.
For the form / version I had (form O), I'd say the MCQ required LOTS of keeping track of whats actually in the question. Concepts alone aren't difficult as long as you know how everything works. Like you don't need to know EVERY single step for like the Krebs cycle in Cellular Respiration, but something like "where does the ETC take place" just place where, reactants, and products type stuff. The MCQ was really a drag though bc it required SOOO much thinking. For ex, it could talk abt a simple process like gene regulation or something, but it'll mention like 5 different proteins with different funtions with like some random mutation which YOU have to keep track of.
FRQ were insanely easy for me, but that's because I know the entire course content wise inside and out. But I would say in general FRQ's are easy even if you don't know the entire course.
Good luck! If you have any other questions let me know D