Question

What is called sea-floor spreading ? ​

Answer 1

Sea-floor spreading is what happens at the mid-oceanic ridge where a divergent boundary is causing two plates to move away from one another resulting in spreading of the sea floor.

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Answer 2

Explanation:

$\underline\red{⛄~Sea-floor~spreading~⛄}$

$\bold\green{~❀~}$ The eruptions on the mid-ocean ridge create new ocean floor made of basalt rocks, which then spread literally from the ridge, which is called ' $\tt\red{sea-floor~spreading}$ ' .