Some isotopes, however, decay slowly, and several of these are used as geologic clocks. Dating rocks by these radioactive timekeepers is simple in theory, but the laboratory procedures are complex. <span>All methods rely on the fact that certain elements (particularly uranium and potassium) contain a number of different isotopes whose half-life is exactly known and therefore the relative concentrations of these isotopes within a rock or mineral can measure the age.</span>
Popcorn, grapes and hotdogs
Answer:
In cells use oxygen to release energy stored in sugars such as glucose. In fact, most of the energy used by the cells in your body is provided by cellular respiration.
Explanation:
