Answer the following question given this paragraph: 

Many people think that any idea that is completely accepted in science is a law. But that is not true. In science, a law is something that always applies under the same conditions. A law explains a fairly simple phenomenon. A theory is much more complex: it tells you why something happens. A law only tells you that it happens. For example, if you hold something above the ground and let go, it will fall. This phenomenon is recognized by the law of gravity ( Figure below ). Some people say that evolution is "just a theory. " But for a complex explanation like evolution, theory is the right word.


Q: In science, what do you call something that always applies under the same conditions?


A:
scientific law