The early stage of protein purification often uses a procedure known as "salting out". this is typically done by treating the protein solution with ?

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 correct answer from the choices listed above is the first option. the scientists need to look at the   validity of data, claims, hypotheses, and observations before  developing an argument. they base their arguments on facts that are present and they make sure they have proofs. 

explanation:

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.