Which of the following molecules did the first life on earth more likely use for extracting energy and carbon?
A) oxygen
B) ATP
C) NADPH
D) water
E) methane

Question

Quizplus · Accepted Answer

The first life on earth likely used methane for extracting energy and carbon because at that time, the earth's atmosphere lacked oxygen, which is necessary for aerobic respiration. Methane is a simple organic molecule that can be broken down through anaerobic respiration to release energy and carbon for the building of organic compounds. ATP and NADPH are molecules used in energy transfer and photosynthesis, respectively, but were likely not available for the first life on earth. Water is important for life, but it is not a source of energy or carbon.

Which of the Following Molecules Did the First Life on Earth