Answer
Selfing is advantageous since it makes plants genetically more uniform (not completely due to the effects of meiosis)βin a stable and uniform habitat, if one then does well, all will do well. The evolutionary dead end comes because the drive to genetic uniformity limits or prevents adaptation to new conditions.
Work Step by Step
Review earlier chapters on evolution, especially with regard to the role of genetic variation in adaptation. Then look up the value of genetic uniformity when there is little or no change in habitat.