When liquid gold becomes a solid, its particles get closer together. which best describes what happened to the gold?

a. the conservation of magnetism
b. the change in solubility in a physical change
c. the change in melting point in a physical change
d. the rearrangement of particles in a physical change

option D. The rearrangement of particles in a physical change.

Explanation:

1) The change occured when a liquid substance becomes a solid is named freezing.

Yes, such as when liquid water becomes ice.

2) Such change is a change of phase or physical state of the matter. As such it is just a physical change: the chemical composition of the substance and the chemical bonds do not change.

3) At atomic or molecular level, what happens with the particles during freezing is that they come closer and are arranged in fixed positons one respect to the each other, so the particles do not slide over others. By occupying a fixed position, the substance acquires a definite shape and volume, and is not able to flow.

the temperature and the pressure affect solubility. temperature affects by changing the properties of the solvent. the increase in pressure increases solubility, the decrease in pressure decreases solubility.

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =