A dynamic planet 9th grade

To study the Geosphere we use:

• There are no methods for study.

• Only direct methods such as surveys.

• Only indirect methods such as seismic method.

• Both direct and indirect methods.

Seismic waves are propagated:

• The more plastic the medium passed through, the faster they are.

• The more rigid the medium passed through, the faster they are.

• The more rigid the medium passed through, the slower they are.

• The more plastic the medium passed through, the slower they are.

S or secondary waves:

• Make materials vibrate so they oscillate horizontally to the direction of propagation and pass through liquids.

• Make materials vibrate so they oscillate horizontally to the direction of propagation and pass through solids.

• Make materials vibrate so they oscillate horizontally to the direction of propagation and cannot pass through liquids.

• Make materials vibrate so they oscillate perpendicularly to the direction of propagation and cannot pass through liquids.

In the Gutenberg discontinuity:

• The P waves increase their speed, the S waves increase their speed, indicating that the lower layer is in liquid state.

• The P waves decrease their speed, the S waves increase their speed, indicating that the lower layer is in solid state.

• The P waves decrease their speed, the S waves stop propagating, indicating that the lower layer is in liquid state.

• The P waves increase their speed, the S waves decrease their speed, indicating that the lower layer is in solid state.

The Earth's mantle is divided into two areas:

• An outer zone with rigid rocks which, along with the crust, form the lithosphere, and an inner zone where, due to the high pressures and temperatures, the rocks are hard and have plastic behaviour.

• An outer zone with plastic rocks which, along with the crust, form the lithosphere, and an inner zone where, due to the high pressures and temperatures, the rocks are hard and have plastic behaviour.

• An outer zone with rigid rocks which, along with the crust, form the lithosphere, and an inner zone where, due to the high pressures and temperatures, the rocks are soft and have plastic behaviour.

The nucleus comprises:

• Nickel and Lithium.

• Iron and Nickel.

• Silicon and Nickel.

• Iron and Silicon.

Wegener's hypothesis was rejected for two reasons:

• These are not the reasons why Wegener's hypothesis was rejected.

• Because he did not provide a satisfactory explanation of which forces moved the continents and because it is impossible for ocean rock masses to float on the rocks of the mantle.

• Because he did not provide a satisfactory explanation of which forces moved the continents and because it is possible for continental rock masses to float on the rocks of the ocean bed.

• Because he did not provide a satisfactory explanation of which forces moved the continents and because it is impossible for continental rock masses to float on the rocks of the ocean bed.

Lithospheric plates have boundaries that coincide with important lithosphere relief such as:

• Ocean ridges.

• All of them are boundaries of lithospheric plates.

• Ocean trenches.

• Large mountain ranges.

Ridges are:

• Elevations of the seabed running for tens of thousands of miles, hundreds of kilometres wide and around 4 km high, with a trench or rift which occupies the central axis.

• Elevations of the seabed running for tens of thousands of miles, hundreds of kilometres wide and around 2 km high, with a trench or rift which occupies the central axis.

• Depressions of the seabed running for tens of thousands of miles, hundreds of kilometres wide and around 4 km high, with a trench or rift which occupies the central axis.

• Depressions of the seabed running for tens of thousands of miles, hundreds of kilometres wide and around 2 km high, with a trench or rift which occupies the central axis.

The sinking of a slab under another causes friction, and this friction leads to earthquakes at numerous points which come together on a dipping plane coinciding with the surface of the sinking slab; this plane is known as:

• Menioff plane.

• Benioff plane.

• Cardiff plane.

• Penioff plane