Answer: The correct answer to the question is option 2
If pressure is applied to a rock until it's volume is reduced by one half how the new density compares to it's original density is ; THE NEW DENSITY IS TWICE IT'S ORIGINAL DENSITY.
Explanation: Density is defined as mass divided by volume,density increases with pressure and it's determined by spaces between atoms in the object being measured.
Density is directly proportional to Pressure,so when pressure increases, Density increases and when pressure decreases,density decreases.
Density is indirectly or inversely proportional to temperature. so when pressure and density increases, temperature remains constant.
This is applicable to the scenerio with the rock in the question,as the pressure on the rock is increasing,the density is increasing too.