Whether globe or plane or cube or rhombus these mountains etc are all PART of the earth, not A PART from the earth. According to your definition a tree or bush or house would disqualify any claim of any flatness. Also you seem to be fixated on the totality of the earth being the surface. If the earth is a globe then the majority of the earth is, ready, solid rock: 25k mile circumference, 8k mile diameter. That's a LOT of solid rock. But there's even more: isn't the sky also part of the earth? Why it sure is! Now conveniently there's no coherent definition of exactly where the sky (which remember is as much a PART OF the earth as the freaking core) ends and 'outer space' supposedly begins. But that notwithstanding what the earth is is EVERYTHING that it is. The tree is a part of the earth just as much as the mountain or flower or beetle or you or I. We are not somehow separate from the earth.