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 made by 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 Ellicott Douglas.Douglas developed a simple technique for dating trees called cross-dating and for a period of over twenty years continued the study of tree rings. He spent much of his time in logging camps near Flagstaff.The Douglas method has been used by many scientists. Some of them used it to examine logs in Indian pueblo ruins; they were able to date the buildings right back to the tenth century. Others used it to date the world's oldest living trees, the bristlecone pines.