. What is the main difference between the outer core and the inner core of the Earth? The inner core is mostly solid iron, the outer core is mostly liquid nickel. The inner core is solid iron and nickel and the outer core is liquid iron and nickel. The inner core is cooler because it's solid and the outer core is hotter and liquid. The inner core is hotter and liquid and the outer core is cooler and solid.

A) The inner core is mostly solid iron, the outer core is mostly liquid nickel

Explanation:

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explanation:

all these collisions do one thing, and that thing is explained in the last option. when dusst, rocks and ice collide, they harden and form giant layers of rocks or hard ice.

d)   to harden materials to form different parts of earth’s layers

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