Question

Arrange the following in proper sequence of their formation
A) Photo autotrophs
B) Anaerobic heterotrophs
C) Free genes
D) Chemoautotrophs
1. A-C-D-B.
2. C-D-B-A.
3. C-B-A-D.
4. A-D-B-C.

Answer 1

Hint: Earth has no life, long year’s back, later after some time so many reactions happened that made the formation of some organic molecules, and these organic molecules form the little more complex molecules such as proteins, carbohydrates, etc.

Complete answer:
Life on the earth began some billion years ago, before that the earth was so primitive, there was no life and there is no oxygen in the earth, and then later the organic molecules that were present on the earth undergo changes and they cause the polymerization of such molecules, some organic molecules such as amino acids they undergo polymerization that form proteins and this protein later undergo further polymerization to form the biomolecules such as proteins, nucleic acids, and the carbohydrates, etc. So genes are first formed on earth as per the above-given sequence.
As there is no oxygen on earth at that time, there were no producers that produce organic carbon, where chemoautotrophic organisms are used to synthesize the organic carbon by inorganic compounds such as iron, sulfur, magnesium so that $2^{nd}$ one in the sequence is chemoautotrophs. And in these chemoautotrophs, there is no synthesis of $Co_2$ and $O_2$ in this process, and the byproducts of the chemoautotrophs are organic methane and sulfur.
Because of this chemoautotrophs, later anaerobic heterotrophs begins to evolve as this also don’t need oxygen for their energy production, and they depend on chemoautotrophs for their food and energy, so the next one in this sequence is anaerobic heterotrophs.
Later there was the development of the photoautotrophs, Where they synthesize the food in the presence of sunlight, and this leads to the formation of carbon dioxide and oxygen, so the next one is photoautotrophs.

The correct option is 2.

Note: The order of sequence of life that originated as per the above-given option are genes first which are formed from biomolecules later than chemoautotrophs, where based on that anaerobic heterotrophs are formed, and finally photoautotrophs are produced.