When human blood is placed in a 2% detergent solution, option 1 states that the red blood cells (RBC) will shrink.

To understand why this happens, we need to know that detergents have the ability to disrupt the cell membrane. The cell membrane is a lipid bilayer that surrounds the RBC and maintains its shape and integrity. When the detergent comes into contact with the cell membrane, it disrupts the lipid bilayer by breaking down the hydrophobic interactions between the lipid molecules.

As a result, the cell membrane becomes more permeable, allowing water to enter the cell through osmosis. In this case, the detergent solution is hypotonic, meaning it has a lower concentration of solutes compared to the inside of the RBC. This osmotic imbalance leads to water entering the RBC, causing it to swell.

However, option 1 is correct because as the RBC swells, the cell membrane starts to detach from the cytoskeleton and loses its shape and integrity. Eventually, the cell membrane collapses and the RBC shrinks.

It`s important to note that options 2, 3, and 4 suggest that the RBC will swell and burst or lyse, but these are incorrect. The