Radiocarbon dating is a technique for determining the age of carbon-based materials derived from live beings. By measuring the quantity of carbon-14 in a sample and comparing it to an internationally accepted reference standard, an age may be determined. Radiocarbon dating is based on the basic principle that all living organisms absorb carbon from the atmosphere and food sources around them, including a small quantity of naturally radioactive carbon-14. When a plant or animal dies, it stops absorbing carbon, but the radioactive carbon it has stored decays.
Essay: Explain how water erosion by groundwater can form a cave. Water sinks into the ground and mixes with carbon dioxide to form carbonic acid. Carbon acid can break down limestone. Some of the limestone gets carried away.
DNA and Mutations. A mutation is a change in DNA, the hereditary material of life. ... So a change in an organism's DNA can cause changes in all aspects of its life. Mutations are essential to evolution; they are the raw material of genetic variation.
