Question

characteristic of structural plains

Answer 1

Structural plains are undisturbed horizontal surfaces are structurally the most depressed areas of the world.
They always border the continents.
They are mainly formed by the subsidence or upliftment of a part of the of the continental shelf or sometimes the sea floor.
Examples-Russian platform,The great plains of USA.

Answer 2

Structural plains horizontal surfaces which are depressed areas of world. They generally are found near costal areas.