Earth blue blood

We have only explored five percent of the ocean. The ocean takes up seventy percent of our planet's surface. By that Logic, we only know about twenty-five or our planet's geography. The sea is like the Earth's lungs, breathing in and out, supplying the Earth with life and balance. We don't know Old the Earth is. We don't know how deep the deepest part of the ocean is. We don't know how vast the universe is, we only know what we know. There are so many things we don't know about our planet. Only God knows.