It StARtS It cell splits to become ter just forty-seven doublings, you en trillion(10,000,000,000,000,000) cells in your body and are ready to spring forth as a human being.

    1And every one of tly o do to preserve and nurture you from t of conception to your last breath.

    You s from your cells. t you te genetic code—truction manual for your body—so itkno only o do its job but every oto remind a cell to keep an eye on its adenosine tripe levels or to find a place fortra squirt of folic acid t’s just unexpectedly turned up. It  for you, andmillions more things besides.

    Every cell in nature is a t are far beyond ts ofy. to build t basic yeast cell, for example, you urize about ts as are found in a Boeing 777 jetliner andfit to a sp five microns across; to persuade tspo reproduce.

    But yeast cells are as not just more variedand complicated, but vastly more fascinating because of teractions.

    Your cells are a country of ten trillion citizens, eaced in some intensivelyspecific o your overall  a t do for you. tyou feel pleasure and form ts. to stand and stretc, tract trients, distribute tes—all t in junior  to make you place and reer you forget to eat again. tlypurring. to your defense tantyou are tened. tatingly die for you—billions of t once in all your years  us take a moment nooregard tion they deserve.

    e understand a little of  ormanufacture insulin or engage in many of ts necessary to maintain a complicatedentity like yourself—but only