The fuel tank of an airplane has a device that measures the fuel’s temperature. Before the airplane took off, the temperature of the fuel was 27°C. After the airplane had been flying for one hour, the temperature of the fuel had decreased to 3°C. Which of the following must have happened to the molecules of the fuel?

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).

you need to stop taking that class