AP Biology · Free-response questions 2025

6 questions, each with its course unit and the official scoring guidelines.

Official paper (PDF) · QuestionsAll AP Bio papers→

Question 3

Open answer
Question 3 — 3. Buffelgrass, an invasive grass species in southwestern desert ecosystems, is threatening the saguaro cactus, a keystone species in these ecosystems. Buffelgrass is drought-tolerant and can survive wildfires. However,…

Source: College Board — AP Biology, Free-response questions, 2025

Question 4

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Question 4 — 4. Twenty million years ago the Caribbean Sea and Pacific Ocean were connected, and water flowed freely between the two bodies of water. Many of the same marine species were found in both areas. Over millions of years,…

Source: College Board — AP Biology, Free-response questions, 2025

Question 5

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Question 5 — 5. Figure 1 shows the reactions of the metabolic pathway used to synthesize amino acid B from amino acid A in cells. Figure 1. Synthesis of amino acid B from amino acid A A. Describe a characteristic of an enzyme’s…

Source: College Board — AP Biology, Free-response questions, 2025

Question 6

Open answer
Question 6 — 6. The ald gene of fruit flies encodes the ALD protein, which is associated with both the centromeres of chromosomes and protein filaments produced during meiosis. In the absence of functional ALD proteins,…

Source: College Board — AP Biology, Free-response questions, 2025

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