Question

earths changing surface online practice
complete this assessment to review what youve learned. it will not co
which statement best explains the theory of plate tectonics? (1 point)
∘ earths crust is formed by the magma that rises in the mantle.
∘ earths crust is composed of rock plates that float on top of the mantle.
∘ earths core consists of rock plates that float on top of the mantle.
∘ earths mantle is made of rock plates that move across the crust.
check answer
remaining attempts 3

Explanation:

To determine the correct answer, we analyze each option based on the theory of plate tectonics:

• Option 1: The crust is not formed by magma rising in the mantle. Magma can form new crust at mid - ocean ridges, but this is not the overall description of plate tectonics.
• Option 2: The theory of plate tectonics states that the Earth's lithosphere (which includes the crust) is broken into several large and small rigid plates that "float" on the semi - fluid asthenosphere (part of the upper mantle). This matches the key concept of plate tectonics.
• Option 3: The Earth's core is not composed of rock plates, and rock plates are part of the crust and upper mantle, not the core.
• Option 4: The mantle is not made of rock plates, and the plates are part of the crust and upper mantle (lithosphere) that move over the mantle, not the other way around.

Answer:

B. Earth's crust is composed of rock plates that float on top of the mantle.