D. Biological activity
Explanation:
The earth's atmosphere became oxygen rich as a result of biological activities. Early earth atmosphere was toxic one and in its reducing state.
- The activities of micro-organisms such as cyanobacteria led to the production of oxygen.
- These organisms manufacture their food in the presence of sunlight and water in the process of photosynthesis.
- The bye product of this reaction is oxygen.
- The intense presence of these living organisms led to the surge in atmospheric oxygen.
Learn more:
Photosynthesis brainly.com/question/4216541
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The organisms that are most closely related (based on the tree above described) are dinosaurs and crocodiles . Thus, option "4" is correct.
<h3>What are Evolution and phylogenetic trees?</h3>
Evolution refers to the natural process of descendence with modification, which is mainly due to natural selection.
Evolution leads to speciation, thereby species are related and they show evolutionary relationships.
A phylogenetic tree is a diagram that represents evolutionary relationships between species that share a common ancestor.
In conclusion, the organisms that are most closely related (based on the tree above described) are dinosaurs and crocodiles.
Thus, option "4" is correct.
Learn more about phylogenetic trees here:
brainly.com/question/8188690
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Answer:
2.ruminating animals have a four chambered stomach.
4. digestion is the process by which food is......(the rest remains the same)
