Explanation:
OK, first of all, let me explain to you, what is a scientific theory...
A scientific theory is an explanation and demonstration of an aspect that exists in the natural world or universe that has been verified by the scientific way through repeated testing of the experiment with accepted protocols of observation, measurements and evaluation of results.
A scientific law is generated in the same procedure as above, but it can predict a wide range of natural phenomena.
Ex-: you are throwing a basketball from the top of a dam to the river. according to physics on earth, it should fall down. it's a law. no matter where you are, that basketball touches down the ground if there's any gravitational force.
But cell theory cannot be assumed to be common throughout the entire universe. Because we may find some other form of life that has some other plans. viruses are not obeying this theory.
*In a nutshell, a law is stable from its' origin. most of the time, it won't change. but theories will change with updating facts of science.
