Answer to Question 1
Scientists were surprised to discover that after the reintroduction of the wolves to Yellowstone, the numbers of Aspen and Willow trees began to recover, the number of bison and beaver increased, and there was less erosion of the river and stream beds.
Answer to Question 2
Other sustainable energy sources could be used as a backup to solar power. Most likely, though, conventional energy sources will be used as a backup to solar power.