If you are asking for a proof on having at least 3 dimensions in space, you can find the physical proof anywhere in your daily life activities. Just the fact that solids have volumes is a proof already that we live in a three-dimensional space. We can move forwards, backwards, sidewards and in all other directions possible.
When you go right into detail, the fundamental laws governing these proofs are very technical. They have differential equations to show as proof. It is too detailed to discuss here. The important things is that, these fundamental laws are what explains the science in our basic activities and natural phenomena:
*Gravitation and planetary motion
* Translation, rotation, magnetic field, forces
* Integrals of equations:
They move in a perpendicular direction to the direction of wave motion. Happy to help!
Answer: 
Explanation:
Given
No of moles 
Temperature 
Initial volume 
Final volume 
Work done in constant temperature process is

Insert the values

Answer:
The correct answer to the question is
a. a compound that conducts electricity when molten
Explanation:
A molecular is solid comprises of a collection of molecules combined together by van der Waals forces and not having covalent or ionic bonds. They are made up of forces atoms or molecules combined by dipole-dipole forces, London dispersion forces or hydrogen bonds. Exmples include graphite and diamonds. The forces between the molecules in molecular solid is also known as intermolecular forces (IMFs)