trillions http://www.ncbi.nlm.nih.gov/pubmed/23829164 Bianconi E et al, 2013 more than 30 trillion living human cells more than 30 trillion life-forms (cells) more than 30 trillion pieces http://www.ncbi.nlm.nih.gov/pubmed/23829164 37 trillion http://www.ncbi.nlm.nih.gov/pubmed/23829164 37 trillion or so cells http://www.ncbi.nlm.nih.gov/pubmed/23829164 http://www.ncbi.nlm.nih.gov/pubmed/23829164 37 trillion cells http://www.ncbi.nlm.nih.gov/pubmed/23829164 http://www.ncbi.nlm.nih.gov/pubmed/23829164 http://www.ncbi.nlm.nih.gov/pubmed/23829164 estimated http://www.ncbi.nlm.nih.gov/pubmed/23829164 http://www.ncbi.nlm.nih.gov/pubmed/23829164 37 trillion trillions 40 trillion cells recent estimates roughly 30 trillion cells