Question

question 5 (1 point)
how does an ocean basin form?
heat and volcanism from earths mantle can cause granitic continental crust to change into basaltic ocean crust.
meteorite impacts caused huge craters that are the precursors to oceans.
continental lithosphere becomes so dense that it sinks.
convection cells in the asthenosphere pull the seafloor apart, and the spreading creates ocean lithosphere in the gap left between the separating pieces.
all of the ocean basins were formed when the earths crust first formed, so there are no new oceans.

Explanation:

Ocean basins form mainly due to seafloor - spreading. Convection cells in the asthenosphere cause the seafloor to spread apart, creating new oceanic lithosphere in the gap. Option 1 is incorrect as the change from granitic to basaltic crust is not the main way ocean basins form. Option 2 is wrong because meteorite impacts are not the primary cause. Option 3 is incorrect as the sinking of continental lithosphere is not the main mechanism for ocean - basin formation. Option 5 is false as new ocean basins can form over geological time.

Answer:

Convection cells in the asthenosphere pull the seafloor apart, and the spreading creates ocean lithosphere in the gap left between the separating pieces.