Book excerpt: CliffsNotes AP Biology 2021 Exam gives you exactly what you need to score a 5 on the exam: concise chapter reviews on every AP Biology subject, in-depth laboratory investigations, and full-length model practice exams to prepare you for the May 2021 exam. Revised to even better reflect the new AP Biology exam, this test-prep guide includes updated content tailored to the May 2021 exam. Features of the guide focus on what AP Biology test-takers need to score high on the exam: Reviews of all subject areas In-depth coverage of the all-important laboratory investigations Two full-length model practice AP Biology exams Every review chapter includes review questions and answers to pinpoint problem areas.