<span> under extreme heat or pressure
crystallize from magma
precipitate from a solution reaction of hot mixture with water and a dissolved substance</span>
I don't know what the options were but a material that is very likely going to be challenging to recognize under a microscope as a mixture is a homogeneous mixture. A homogenous mixture is uniform and thus hard to recognize as a mixture. An example is water!
Nearly all life on Earth gets its energy from the sun, and the sun gets its energy through the process of nuclear fusion, which is why these type of energy is important to life on Earth.
