ScienceDaily: More rainfall during the growing season may have led to one of the most significant changes in Earth's vegetation in the distant past, and similar climate changes could affect the distribution of plants in the future as well, a new study suggests. In a report in Science Advances, an analysis was done of mammoth and bison hair, teeth and bones, along with other data. It concludes that a changing climate -- particularly increasing rainfall and not just atmospheric carbon dioxide -- explains the expansion...