0 the cells in the embryo of a human or animal that develop into skin, hair, and the nervous system --
1 the cells in the embryo (= growing organism before it is born) of a human or animal that develop into skin, hair, and the nervous system --
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
Можем да го завършим стъпка по стъпка, колкото и дълъг да е пътят и не може да бъде завършен, колкото и кратък да е пътят, ако дори не маркирате отпечатъка си.