AP BIOLOGY

Detailed explanation-1: -Radiometric dating . Hypotheses of absolute ages of rocks (as well as the events that they represent) are determined from rates of radioactive decay of some isotopes of elements that occur naturally in rocks.

Detailed explanation-2: -After the death of the organism, the amount of radiocarbon gradually decreases as it reverts to nitrogen-14 by radioactive decay. By measuring the amount of radioactivity remaining in organic materials, the amount of carbon-14 in the materials can be calculated and the time of death can be determined.

Detailed explanation-3: -Most absolute dates for rocks are obtained with radiometric methods. These use radioactive minerals in rocks as geological clocks. The atoms of some chemical elements have different forms, called isotopes. These break down over time in a process scientists call radioactive decay.

Detailed explanation-4: -Absolute age is the numeric age of a layer of rocks or fossils. Absolute age can be determined by using radiometric dating.

Detailed explanation-5: -High-precision laboratory analyses are then used to measure the amounts of radioactive parent isotope and stable daughter product in the minerals. Once these quantities have been measured, the half-life of the radioactive isotope is used to calculate absolute age of the granite.