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Answer:</h2>
Option A. Bacteria.
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Explanation:</h2>
- It is presumed that, over millions of years of evolution, abiotic molecules evolved into the self-replicating molecules by means of natural selection.
- Cyanobacteria, or blue-green algae is a bacteria which was one of the oldest fossils found on earth. These microbes conduct photosynthesis: using sun light, water and carbon dioxide to produce carbohydrates and oxygen.
- Cynobacteria played a major role in forming oxygenated atmosphere.
- The first living things on the planet Earths was single-celled micro-organisms which lack a well defined cell nucleus were known as prokaryotes, and bacteria belongs to prokaryotes ans hence among given options bacteria matches the most for the first life form on earth.
Result: Among the given choices bacteria was most similar to first living things on earth.
The primary function of cellular respiration is to break down food molecules and generate ATP.
<h3>What is cellular respiration?</h3>
Cellular respiration is the process by which living organisms obtain energy in form of ATP by breaking down food molecules in their cells.
Cellular respiration occurs in all living organisms because energy is required for their daily metabolic activities.
Therefore, the primary function of cellular respiration is to break down food molecules and generate ATP.
Learn more about cellular respiration at: brainly.com/question/13721588
I am not sure but here is a link that should help :)
https://www.ncbi.nlm.nih.gov/pubmed/9971764