Environmental Science Study Library.

About the exam

The AP Environmental Science exam runs 2 hours 40 minutes. Section I (60%) has 80 multiple-choice questions in 90 minutes. Section II (40%) has 3 free-response questions in 70 minutes. All three FRQs are 'document-based' in the sense that stimulus material (tables, graphs, or passages) may accompany each prompt.

How to use this library

Each unit page below contains the full list of key topics, common exam errors to avoid, and a study guide section. Work through units in order, or jump directly to the unit with the highest exam weight — those are your highest-leverage study targets.

Exam strategy notes

• The FRQ types are predictable: identify a problem, describe a specific solution, explain environmental consequence. Practice the solution-then-consequence sentence structure.
• Every energy source has environmental tradeoffs. You must name specific impacts — 'solar panels require large land areas and rare materials; wind turbines cause bird mortality.'
• Calculation questions (Rule of 70, trophic energy transfer, fuel efficiency) appear every year. Set up the formula, show work, and include units.
• HIPPO, ENSO, demographic transition model, primary vs. secondary succession — memorize the frameworks and their specific vocabulary.