What percentage of the planet beneath us is inaccessible by
humans?

About 70 percent

Explanation:

Around 70 percent of the planet beneath us is inaccessible by humans. This is because a large and majority part of the planet is covered by water. This include seas, oceans, rivers etc. These are where sea animals thrive and a large amount of ocean floor has been inaccessible by humans.

However due to urbanization a larger portion of the land has been explored and been accessible to humans.

within these regions are all the major types of biomes in the world. a biome is a community of animals and plants spreading over an extensive area with a relatively uniform climate. some diverse biomes represented in north america include desert, grassland, tundra, and coral reefs.