Psalm 145:9 "God is good to all. His compassion shelters all His creatures." God gives us everything we need. Just as the turtle has a shell for protection and the beaver has teeth to cut through wood to make a home, we have what we need to overcome our challenges and to help others along the way.
The song begins with a Midrash about how God guides the leaf to just the right spot to shelter a worm from the sun. That is how involved He is in the details of our lives and how much He cares for us. The thought is extended to include a shell being guided to just the right spot to protect a seed of a tree and a young woman guided to just the right spot to protect a child.