Complex sentence: Vents that issue volcanic material (including lava and ash) and gases (mainly steam and magmatic gases) can develop anywhere on the landform and may give rise to smaller cones such as Puu Ōō on a flank of Hawaii's Kīlauea.
Split into simpler sentences: Vents that issue volcanic material (including lava and ash) and gases (mainly steam and magmatic gases) can develop anywhere on the landform. Many of these vents give rise to smaller cones such as Puu Ōō on a flank of Hawaii's Kīlauea.