Final answer:
Gymnosperms and angiosperms were the dominant land plants during the latest Paleozoic and most of the Mesozoic eras.
Step-by-step explanation:
Gymnosperms, which are heterosporous seed plants that produce seeds, appeared during the drier Permian period and became the dominant group during the Triassic. Angiosperms, on the other hand, bear flowers and fruits, expanding the possibilities for pollination and seed dispersal.
Gymnosperms preceded angiosperms in dominance, but by the middle of the Cretaceous period, angiosperms surpassed gymnosperms as the dominant plant life in terrestrial habitats.