Answer:
C-magma
Step-by-step explanation:
Sea-floor spreading is a geological process in which new oceanic crust is formed as magma rises from the mantle and solidifies at the mid-ocean ridges. The mantle is the layer of the Earth that lies between the crust and the core. It is a hot and partially molten layer of rock that flows slowly over time, and it is the source of the magma that creates new oceanic crust.
At the mid-ocean ridges, which are underwater mountain ranges that run along the center of the ocean basins, magma rises up from the mantle through cracks and fissures in the Earth's crust. As the magma cools, it solidifies and forms new oceanic crust. Over time, this process causes the ocean floor to spread apart and move away from the mid-ocean ridges, creating new oceanic crust.
The process of sea-floor spreading is a key component of plate tectonics, the theory that describes how the Earth's crust is made up of large, moving plates that interact with each other. As new oceanic crust is formed at the mid-ocean ridges, it moves away from the ridges and eventually collides with other plates, causing subduction and other geological processes. Understanding the process of sea-floor spreading is essential for understanding the dynamics of the Earth's crust and the formation of the ocean basins.