You are given a science question (easy-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]: Plants growing in a pond release a gas that fish need to survive. Which gas do the plants release that fish use?  
 (A) helium (B) hydrogen (C) nitrogen (D) oxygen
[A]: D


[Q]: The Sun is classified as  
 (A) an organism (B) a decomposer (C) a star (D) a planet
[A]: C


[Q]: Which statement about the genetic traits of humans is true?  
 (A) Recessive forms of genes are always visible in offspring. (B) Visible traits are the same for each member of a family. (C) Dominant forms of genes are always inherited from both parents. (D) Visible traits depend on the dominant and recessive forms of genes from each parent.
[A]:
D