The correct answer is c trachea
Body parts of unrelated organisms that serve the same function are examples of convergent evolution.
<span>Convergent evolution is the phenomenon when the different species independently create similar features. Those features can be structures that have similar form or function. This happens because organisms have been adapted to similar environments or ecological niches.</span>
Having one theory is setting a limit on your potential and the potential of the overall theory and subject you are working on. Having multiple theories gives you a broader idea and perspective of what is going on, and even though one may slightly contradict the other, it is okay because that is what theories are for.
To the point, scientists usually have more than one theory so that they can gain a broader perspective on the matter and maybe even increase the chance of being correct on the matter.
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The two serous membranes of pericardium are :visceral pericardium,parietal pericardium.