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. ████████ ██████ ███ █████ ██████ ██ █ ██████████ ███████████ ████ ███ ███ ████ ██ ████████ ███ ████ ██ ███████ █████ █████ ██ ███ ████ ███████ ███ ████ ██ █████ █████ ████ ████ ██ █████ ██████████ ███ ███████ ████ ███████ ██████████ ███ ████████ ████ ██ ██████ ███ ████ ██ ████████ ██ ███ ████ ████ ██████
How could lightning have produced the first amino acids on Earth, even though Earth’s atmosphere at that time had a lot of oxygen, and amino acids break apart unless the spark that produced them occurs in an atmosphere that has a lot of hydrogen and not much oxygen (a “reducing” atmosphere)?
The correct answer should explain how there still could have been a “reducing” atmosphere necessary to allow the first amino acids to form and persist, even though Earth’s atmosphere had a lot of oxygen (and so was not a “reducing” atmosphere).
Assuming that the scientists' current ██████ █████ ███████ ██████████ ██ ███ ████ ████ █████ ██ ████████ █████ ███ ██ ███ ██████████ ██ █████ █████ ████ ████ ██ ███████ ███ █████████ █████ ████ ████████ ███ █████ █████ █████ ██ ██████
Meteorite impacts at ███ ████ ████ █████ ██ █████ ███████████ ███████ █ ████████ ██████████ ██████ ███ ██████ █████
A single amino ████ █████ ████ ████ ██████████ ██ █████ ███ █████████ ██ ████ ██ ██████
Earth's atmosphere has ███████ █████████████ █████ ████ █████ ██████
Lightning was less ██████ ██ █████ ██ ███ ████ ████ █████ ████ ██ ██ ████
Asteroids contain amino ██████ ███ ████ ██ █████ █████ █████ █████ ███████ ██ ██████████ ██████ ████ ██████