What is the difference between quantum mechanics and relativity theory? which one is more accurate and we need?

What is the difference between quantum mechanics and relativity theory? which one is more accurate and we need to know better?





Thank you.|||Quantum mechanics (QM) is more accurate, its solution space is two maybe three particles at a time, and is based on some arbitrary constants chosen to make it work.





Relativity theory (GR) provides solutions for solar systems to dust grains without aid of Dark anything. And its constants (when used) are the familiar ones of Newtonian gravitation and Maxwell's EM.





Neither is more than a theory, whatever replaces them will only be a theory, and QM and GR will continue to be used inside their domains of applicability.





What we need to know better, are the limitations of Science.