Final answer:
Annexin V binds to phosphatidylserine (PS) and can be used to detect apoptotic cells in the lab.
Step-by-step explanation:
Annexin V is a molecule that specifically binds to phosphatidylserine (PS), which is exposed on the surface of apoptotic cells. By using Annexin V, researchers can detect and identify apoptotic cells in the laboratory. This is because during apoptosis, PS is externalized and Annexin V can bind to it, allowing for the visualization and quantification of apoptotic cells.