Answer:The mid-ocean ridges are higher in elevation than the surrounding ocean floor primarily because the crust at the mid-ocean ridge is younger and therefore hotter and less dense than the surrounding oceanic crust.
When new oceanic crust is formed at a mid-ocean ridge, magma rises up from the mantle and solidifies, creating new crust. This new crust is still hot and less dense than the surrounding older crust, causing it to sit higher on the ocean floor. Over time, the new crust cools and becomes more dense, causing it to gradually sink and move away from the mid-ocean ridge.
In addition to being younger and less dense, the crust at the mid-ocean ridge is also thicker than the surrounding oceanic crust. This is because the process of seafloor spreading at the mid-ocean ridge causes the magma to spread out and solidify over a wider area, resulting in a thicker crust.
Therefore, the primary reason why the mid-ocean ridges are higher in elevation than the surrounding ocean floor is that the crust at the mid-ocean ridge is younger, hotter, less dense, and thicker than the surrounding oceanic crust.
Step-by-step explanation: