To calculate the relative age of rocks, geologists use the rate of radioactive decay of isotopes present in their samples. What is the term used for the original amount of the elemental isotopes being investigated?
A rare earth isotopes
B. Son isotopes
C. daughter isotopes
D. parent isotopes

Some familiar products contain some of the same types of atoms. for instance, the chemical formula for baking soda is nahco 3. the chemical formula for liquid bleach is naclo, and the chemical formula for table salt is nacl. which choice best describes why these three products have some of the same types of atoms in common?