In an experiment designed to show how life may have begun on Earth, scientists demonstrated that an electrical spark-or lightning-could produce amino acids, the building blocks of Earth's life
(So you need amino acids for starting life, and sparks/lightning produces it). However, unless the spark occurs in a "reducing" atmosphere, that is, one rich in hydrogen and lean in oxygen, amino acids do not form readily and tend to break apart when they do form
(reducing atmosphere is necessary for spark to form stable amino acid). Scientists now believe that Earth's atmosphere was actually rich in oxygen and lean in nitrogen at the time life began (
But earths atmosphere was not "Reducing" at the time when amino acids formed).Assuming that the scientists' current belief about Earth's atmosphere at the time life began is correct, which one of the following, if true, would most help to explain
how lightning could have produced the first amino acid on Earth?
So we need something that may explain why amino acids formed in non reducing atmosphere OR How reducing atmosphere was developed/generated?(A) Meteorite impacts at the time life began on Earth temporarily created a reducing atmosphere around the impact site.
(CORRECT: Explains our prethinking)(B) A single amino acid could have been sufficient to begin the formation of life on Earth.
(Wrong: Does not explain HOW exactly that ONE amino acid formed)(C) Earth's atmosphere has changed significantly since life first began.
(Wrong: Atmosphere has CHANGED SINCE life began, implies that atmosphere was oxygen rich when life began and does not explain how reducing atmosphere was provided)(D) Lightning was less common on Earth at the time life began than it is now. (Wrong: does not explain role of reducing atmosphere)
(E) Asteroids contain amino acids, and some of these amino acids could survive an asteroid's impact with Earth.
(WRONG: the argument is not considering aminoacids from asteroids: Out of scope)