TASK DEFINITION: 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.
PROBLEM: One substance found on Earth is more stable as an elemental gas than as part of a solid compound. As a result, this substance is very abundant in the atmosphere. Which substance exhibits these traits?
(A) argon (B) chlorine (C) nitrogen (D) oxygen

SOLUTION: C

PROBLEM: The North America Nebula is named for its similarity in shape to the North American continent. It was discovered within the Milky Way by astronomer William Herschel in 1790. What was Mr. Herschel most likely observing?
(A) the explosion following the collapse of a star (B) a dense cluster of stars of varying magnitudes (C) meteorites as Earth passed through the tail of a comet (D) a cloud of hydrogen gas and dust where stars are born

SOLUTION: D

PROBLEM: What is the mass of an asteroid with a speed of 200 m/s and a momentum of 2,000 kg x m/s?
(A) 10 kg (B) 1,800 kg (C) 2,200 kg (D) 400,000 kg

SOLUTION:
A