LAURA INGALLS WILDER'S FAMILY LIVED FOREVER IN SOUTH DAKOTA SINCEA....

8. Laura Ingalls Wilder's family lived forever in South Dakota sinceA. 1867 B. 1869 C. 1879 D. the age of 65Passage 2:As trees grow old they add a new ring for each year, this discovery, it seems, was first madeby Leonardo da Vinci, the famous Italian painter and scientist. It took a long time, however,before the serious study of tree rings started; this was done in Arizona by Andrew EllicottDouglas.Douglas developed a simple technique for dating trees called cross-dating and for a periodof over twenty years continued the study of tree rings. He spent much of his time in loggingcamps near Flagstaff.The Douglas method has been used by many scientists. Some of them used it to examinelogs in Indian pueblo ruins; they were able to date the buildings right back to the tenthcentury. Others used it to date the world's oldest living trees, the bristlecone pines.