Evolution Question 100
100. Which was absent in the atmosphere at the time of origin of life?
(a) $NH_3$
(c) $O_2$
(b) $H_2$
(d) $CH_4$
Show Answer
Answer : c
Hints & Solution
(c) Oxygen gas was not present due to reducing atmosphere, it only came to existence after the evolution of photosynthesis process.