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").

[Q]: Fact1: Many corals secrete an exoskeleton that builds up to become a coral reef., Fact2: Good examples are Bubble coral, Elegance coral, Frogspawn and other Euphyllia corals., Question: What is secreted by organisms like frogspawn to become a reef? (A) exocrine glands (B) food and shelter (C) exoskeleton (D) bones (E) Energy (F) Chemical energy (G) plasma (H) Energy.
[A]: C


[Q]: Fact1: Bottleneck effect occurs when a population suddenly gets much smaller., Fact2: Fishing pressure is relatively low due to a smaller human population., Question: What can make the bottleneck effect occur in fish? (A) increased habitat (B) acid rain (C) humans (D) Winter (E) increased food (F) storms (G) increased resources (H) Toxicity
[A]: C


[Q]: Fact1: an aquatic animal requires great amounts of water to survive, Fact2: Fish can survive in water by using their gills to extract the dissolved oxygen., Question: What requires great amounts of water to use their gills to extract dissolved oxygen? (A) most cephalopods (B) alligators (C) starfish (D) aquatic animals (E) Jellyfish (F) water foul (G) platypus (H) Lobsters
[A]:
D