In order to read the publications of his peers, or read his own notes of the work
that he did on the previous day, or find his coffee mug on his desk in the lab, the
research scientist must arrange to have each of them illuminated with visible
wavelengths of light, and then he must catch the light reflected from each of them
with his eyes.
Density can be any number, as long as it has the right units.
A unit of density has to be (a unit of mass) divided by (a unit of volume).
The most common one is gram/cm^3.
The answers A, this is because Ice is originally water and when water goes below it's freezing point it turns into ice
