Are you looking for evolution, or evolution by natural selection?
Answer:
It is well known that in biological compounds, such as proteins; a small change on its structure modifies its function to send a different signal or even to not have a function at all.
Talking about cohesin, this protein has been implicated in the development of certain types of tumors, because it takes a fundamental role in the cellular division and the 3D structure of the genome. Cohesin SA1, for example, maintains differentiated the TADs and it is essential for the organization of the topological domains of the genome, while the Cohesin SA2 is much more versatile and can regulate the expression of the genes within TADs, it is also capable to bond to some transcription factors creating local loops.
Some mutations on this protein can also be involved in the origin of rare diseases.
The answer is: [A]: "osteoblasts" .
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Salinity and density share a positive relationship. As density increases, the amount of salts in the water—also known as salinity, increases. Various events can contribute to change in the density of seawater. Salinity can decrease from the melting of polar ice or increase from the freezing of polar ice.