What are the principles related to absolute, relative, carbon, or radioactive dating

The atoms of some chemical elements have different forms, called isotopes. These break down over time in a process scientists call radioactive decay. Each original isotope, called the parent, gradually decays to form a new isotope, called the daughter. Each isotope is identified with what is called a ‘mass number’. When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.

answer; i do believe the correct answer is (river); /// good luck

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.