Answer:
Answer is Ammonium sulfate.
Explanation:
The method of adding ammonium sulfate to a protein solution is known as precipitation. This is because the addition of ammonium sulfate will reduce or decrease the solubility of the protein. And as the ammonium sulfate is being increased, so also the solubility of the protein will be decreasing.
And at the long run, the protein will be precipitated. This is what is referred to as the 'salting out' procedure.
I believe the miRNAs control gene expression by binding to mRNAs and degrading them or blocking their translation. The microRNAs are short non coding RNAs which function to regulate the process of gene expression. They bind to the 3-UTR of the target mRNAs and repress the production of protein by destabilizing the mRNA and translational silencing.