Various adaptations of seed plants helped them to become dominant. Pollen and seeds can lie dormant for a long time, allowing survival in harsher, especially drier, habitats than if these are not present. Flowers and their interactions with pollinators help improve the efficiency of reproduction, and seeds contain nutritive material which helps guarantee the survival of new, weak sporophytes.
Work Step by Step
To see this, review the chapter and make a list if distinguishing characteristics of seed plants. Then look at each and ask yourself how this would allow better survival or dispersal to help these plants become dominant on Earth.