What kind of bio questions are you missing?
Are they purely knowledge-based? (random questions) Or are they conceptual? (Like the reason why C4 photosynthesis tries to move CO2 to bundle sheath)
Depending on what you're getting wrong, I think the strategy would also be different.
If knowledge-based, I'd start going through LOTs of different sources of info (feralis notes, dat bootcamp, campbell's , destroyer, etc)
If concept-based, you could focus in on specific topics to really understand what's going on.