The correct answer is option 4 - All of the above are correct.
Carbon-14 is measured in tree rings, ice cores, and soil samples to establish the age of organic materials. All listed options are correct, and these measurements help to correct for changes in atmospheric carbon ratios over time.
Levels of Carbon 14 (Carbon-14) can be measured in various types of samples to determine the age of organic materials. These samples include tree rings, ice cores, and soil samples; hence, all of the above-mentioned options are correct.
Tree rings provide a record of the atmospheric carbon isotope ratios year by year, while ice cores can show past atmospheric conditions, including greenhouse gas concentrations over many years. Soil samples can also contain organic material that has preserved Carbon-14, providing another medium for radiocarbon dating. The dating accuracy is influenced by changes in the Carbon-14 to Carbon-12 ratio in the atmosphere, which is corrected for by using additional data such as tree ring dating.