Scientists are unsure how many cells exist in the human body; estimates range from 10 to 100 trillion. But you once existed as a single cell-for about half an hour.

• 科学家们还不能确定,究竟有多少个细胞存在于人体内,估计大约有10至100万兆不定。但,你曾以一个单细胞的形式存在,而仅是半小时而已。