<span>During the twentieth century, absolute date was added to the relative time scale. </span>Geologic time scale uses both relative and absolute dating techniques. <span>Soon after the discovery of radioactivity, geologists used radioactive isotope decay to develop a method for determining absolute ages of rocks</span>
Answer:
B. puberty because it's still a stage of pre adult hood
A substance with pH 6 would be an acid, because it's 1pH to the left of a neutral substance
Used by people is the answer. :-)
