Sentence:  Mike stopped to cherish all his brother selves , the many threes-fulfilled on Mars , corporate and discorporate , the precious few on <WSD>Earth</WSD> - the unknown powers of three on Earth that would be his to merge with and cherish now that at last long waiting he grokked and cherished himself . 
Meaning of the word marked with <WSD> tags:  the 3rd planet from the sun; the planet we live on