What product is formed by the stain of proteins present in blood using Amino Black?

When using Amino Black to visualize proteins in blood stains, the process involves a dye that specifically interacts with amino acids and proteins, resulting in a distinctly colored outcome. The choice indicating a blue-black product reflects the expected chemical reaction when Amino Black binds to the proteins present in the blood. This binding leads to a blue-black coloration, which stands out against the substrate, allowing for effective visualization of the blood stains.

The other options do not accurately describe the outcome of using Amino Black. A purple highlighted image does not correspond to the dye's reaction with proteins. Similarly, a yellow-brown residue and a green fluorescent marker are not products formed through the use of Amino Black with blood, making them irrelevant in the context of this staining technique. Therefore, the blue-black product is the only correct and expected result when proteins in blood are treated with Amino Black.