In plants, all cells contain a gene that codes for the production of the pigment chlorophyll. However, chlorophyll is present primarily in leaf cells. Which statement best explains the reason for the absence of chlorophyll in other plant cells? The gene for the production of chlorophyll is lost. The gene for the production of chlorophyll is altered. The gene for the production of chlorophyll is not replicated. The gene for the production of chlorophyll is not expressed.