Explanation: The material which is less dense, means it is lighter in weight. Such substances tend to move more towards the crust of the Earth, whereas the heavier substances like iron, is more towards the core or centre of the Earth. This is because heavier substances tend to sink deeper. That’s why the light elements are found in the crust section of the Earth.
In the Earth's crust, movement of materials is as a result of thermal convection that is occurring within the earth's crust.
When thermal convection occurs, the warm, less dense material inside earth rises towards the crust , while the cool and denser material with sink towards the outer core.
This rising of warm, dense material and sinking of cool, denser material causes a shift in the tectonic plates and stimulates the release of a convection current.
I believe the correct answer among the choices listed above is the last option. Plants seemed to evolve in the order of bryophytes, gymnosperms,angiosperms. Bryophytes are mosses that lack vascular tissue. Gymnisoerm do not have seeds but have vascular tissue. Angiosperms have flowers and seeds for mating.
