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: Earth is composed of layers of material with different properties. Which of the following is most likely to be in constant motion?  
 (A) core (B) mantle (C) oceanic crust (D) continental crust

A: B
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Q: Which statement best describes the development of a human embryo?  
 (A) A single cell becomes many cells. (B) Each cell has a different function. (C) Many cells combine to form one cell. (D) All the cells have the same function.

A: A
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Q: When a skydiver jumps from a plane, the open parachute will increase the air resistance by  
 (A) reducing fluid friction. (B) increasing surface area. (C) increasing terminal velocity. (D) decreasing mass.

A:
B
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