All of the factors that can change in an experiment are called variables.

Which of the following is true about the variables in an experiment?

I'm not sure what your asking buddy.. but i know that you can weld two peices of steel by pure force and pressure.

The best answer is (a) which is universal law is in effect at all times. it is constantly at play in everything we do and governs our lives. it is also important to note that universal law applies to not only everything on earth, but everything in the universe as well, which is another reason why it is in effect at all times.