An Investigator Couples a Photoactivatable Fluorescent Compound to Actin Monomers

An investigator couples a photoactivatable fluorescent compound to actin monomers and injects the labeled actin into live cells.She then allows the labeled actin to be incorporated into actin polymers in the cell.By shining light of a specific wavelength in a small rectangular‐shaped region of the lamellipod,she could turn on the fluorescence of the labeled actin and observe how the labeled filamentous actin behaved in motile cells.If she activates a region at the front of the lamellipod,what will she observe?

A) disassembly and reassembly of actin filaments as the cell moves forward
B) actin filaments remaining organized as the cell moves forward
C) actin filaments remaining stationary relative to the substrate as the cell moves forward
D) actin filaments remaining organized AND moving relative to the substrate as the cell moves forward
E) actin filaments remaining organized AND stationary relative to the substrate as the cell moves forward