1.) how many layers does the earth's mantle have?
2.) the are in the middle of the mantle. in the mantle is the this is a partially melted part of the mantle.
3.) tectonic plated make up earth's and are made of
4.) define the theory of tectonic plates.

i'm assuming that the correct answer is indeed the first one/ "a"..

solute : a solute is a substance that is dissolved in another substance is known as a solvent. it is mixed with a special mixture know as homogeneous mixture.

solvent: a solvent is a substance that dissolved a solute, which results in a solution is known as solvent.