"both have no direct relationship but a free efficient expression binds them" what are they?

Answer

DNA and RNA

Explanation:

As the question indicates that they do not have a direct relationship with each other but there is an indirect process that links them. If we talk about molecular biology, DNA and RNA are two important molecules which form the basis of our every structure or function.  It is important for the timely activity of these two molecules so that every organism performs their activities timely.

Free efficient expression

if we say there is a free expression system that binds them it refers to the process of transcription and translation during which DNA is converted to RNA and RNA sequence is converted into a sequence of proteins. The synthesis of protein is the final stage where you can say that DNA and RNA are processed to form a final product that is protein.

Hope it help!

the electromagnetic energy from the sun arrives in the form of visible and invisible light.