instruction:
In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").
question:
Fact1: when a metal rusts , that metal becomes orange on the surface, Fact2: Iron rusts in the presence of oxygen and water., Question: Exposure to oxygen and water can cause iron to  (A) decrease strength (B) melt (C) uncontrollable burning (D) thermal expansion (E) turn orange on the surface (F) vibrate (G) Extremes of temperature (H) levitate
answer:
E


question:
Fact1: Biomass is the total mass of organisms at a trophic level., Fact2: Producers make up the first trophic level, primary consumers the second, and so on., Question: What is the total mass of primary consumers (A) Plants (B) animals (C) food (D) Mountains (E) Biomass (F) decreases (G) all matter (H) Weight
answer:
E


question:
Fact1: Aging is associated with the death of cells., Fact2: Cell death is natural., Question: What is natural? (A) wetland (B) aging (C) iPhones (D) immortality (E) magic (F) Light (G) Spruce (H) wind
answer:

B