We have fingernails to protect our fingers and toes acting as tiny shields. But why do fingernails when torn tear across the nail instead of down towards the nail base? Research has proven that it takes double the energy to cut nails downward opposed to across the nail base.
Nails are made of 3 layers of keratin specifically arranged: The top and bottom have randomly packed fibers to give the nail its strength. The middle layer holds the key to crosswise tearing with keratin fibers running parallel to the base of the nail.
God in His wisdom, covers all design aspects, even the smallest details for our lives: even the way the fingernail tears!