Which statement is supported by einstein's postulates of special relativity?
the laws of physics change, depending on the state of motion of the observer.
the laws of physics change, depending on the reference frame of the observer.
the speed of light through empty space is constant regardless of the state of motion of the observer.
the speed of light through empty space depends on the state of motion of the observer.

The speed of light through empty space is constant regardless of the state of motion of the observer.

Explanation:

Special relativity was proposed on 1905 by Einstein, who developed his theory based on the following two postulates:  

1. The laws of physics are the same in all inertial systems. There is no preferential system.  

2. The speed of light in vacuum has the same value for all inertial systems.  

According to these postulates,  it can be affirmed that any measurement on a body is made with reference to the system in which it is being measured. In addition, it deals with the dilation of time stating that time passes at different rates in regions of different gravitational potential. That is, the greater the local distortion of space-time due to gravity, the slower the time passes.  

On the other hand, following what relativity establishes, bodies within a gravitational field follow a curved space path.

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force