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").

[EX Q]: Fact1: acid rain has a negative impact on water quality, Fact2: Sulfur dioxide causes acid rain., Question: What has a negative impact on water quality? (A) Reverse osmosis (B) fossil fuels (C) Fresh water (D) Carbon filter (E) chlorofluorocarbons (F) Sulfur dioxide (G) Pollution (H) harmful substances
[EX A]: F

[EX Q]: Fact1: Hormones control many cell activities, so they are very important for homeostasis., Fact2: Hormones travel in the bloodstream to cells that are called target cells a., Question: what allows molecules to travel to control many cell activities (A) skin (B) heat energy (C) animal transport (D) bloodstream (E) Chemical energy (F) nasal passage (G) movement (H) fat tissue
[EX A]: D

[EX Q]: Fact1: Male dogs use pheromones in urine to mark their territory., Fact2: Pheromones are a sub-category of semiochemicals., Question: What do dogs use to mark their territory? (A) water (B) Chemicals (C) layers of fat (D) food (E) Animal fur (F) heat energy (G) Scratches (H) heat produced
[EX A]:
B