Question

Abiogenesis occurred about how many billion years ago?
A. \[1.2\] billion
B. \[1.5\] billion
C. \[2.5\]billion
D. \[3.5\]billion

Answer 1

Hint: Abiogenesis is a scientific theory according to which life appeared on Earth through spontaneous natural means due to the conditions available at that time. In simpler terms, life emerged from non-living matter. Simple elements fused to produce compounds; the compounds became more organised and involved various substances. Finally, simple organic compounds were developed and joined to form complex molecules such as amino acids.

Complete answer:
Option A. \[1.2\] billion: Approximately \[1.2\] billion years ago, at the time of Mesoproterozoic Era, the first complex life forms were appearing on Earth and the major portion of life was still aquatic.
Option A. Is not correct.
Option B. \[1.5\] billion: About \[1 - 1.5\] million years ago, the inner core of the Earth was formed, as it froze from the surrounding molten outer iron core.
Option B is not correct.
Option C. \[2.5\] billion: About \[2.5\] billion years ago, the Great Oxidation Event or GOE occurred. It consisted of a series of chemical changes. After that the amount of oxygen in the Earth’s atmosphere increased.
Option C is correct.
Option D. \[3.5\] billion years ago: Abiogenesis occurred about \[3.5\] billion years ago. Such a process could not occur on Earth today, as the conditions that existed during that time are not available now.
Option D is not correct.

So, the correct answer is “Option C”.

Note:
For years the topic of debate among scientists was whether DNA, RNA, or proteins came first. DNA serves as the primary mode to store genetic information, and proteins act as catalysts. RNA is nucleic acid that can serve as a genetic library as well as can catalyse reactions. This ability makes RNA the best candidate to have commenced the first life on Earth.