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: When air rises over the open ocean, a low pressure system is formed. Which factor increases the potential of a low pressure system developing into a hurricane in the Northern Hemisphere?
(A) cool ocean currents circulating towards the equator (B) increased volcanic activity in the upper latitudes (C) cold air moving south from the North Pole (D) warm water temperatures in the tropics

A: D
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Q: Which of these will most likely result from small meteoroids entering the atmosphere of Earth?
(A) a decrease in air temperature (B) the appearance of shooting stars (C) an decrease in atmospheric ozone (D) the appearance of the Northern Lights

A: B
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Q: A cow and a frog have similar bone structures in their forelimbs. Both have phalanges, radius, ulna, and humerus bones. However, the cow and frog are animals with very different life cycles from each other. Which most likely describes why the body structures of these animals are so similar?
(A) Both have undergone similar mutations. (B) Both descended from a common ancestor. (C) Both reacted similarly to environmental pressures. (D) Both spread out from the same geographical region.

A:
B
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