You are given a science question (hard-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Q: Nectar is a sweet liquid that some flowering plants produce. A hummingbird drinks nectar from a flower. When a hummingbird drinks nectar, pollen from the flower sticks to the hummingbird's beak. The picture shows a hummingbird drinking nectar from a flower. Which statement explains the role of a hummingbird in the life cycle of a flowering plant?  
 (A) A hummingbird carries food to the plant. (B) A hummingbird helps the plant reproduce. (C) A hummingbird protects the plant from predators. (D) A hummingbird makes the flowers produce nectar.

A: B
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Q: How many valence electrons does selenium have?  
 (A) 3 (B) 5 (C) 6 (D) 8

A: C
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Q: Which is a characteristic of a dog that is most likely a result of its environment?  
 (A) its color (B) its length of ears (C) its food preference (D) its ability to see in the dark

A:
C
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