At about 4 billion , multicellular organisms would arise .

四十亿岁的时候，多细胞的有机生物出现了。

The worm is the deepest living multicellular terrestrial organism on earth .

这种蠕虫是地球上生活在最深处的多细胞陆地生物。

He said multicellular organisms likely evolved in many places , but the fossils haven 't yet been found .

他说多细胞生命可能在多处地点演化，只是其化石尚未被发现而已。

When scientists did find multicellular organisms , they assumed that they 'd sunk from oxygen-enriched waters .

而当科学家们确实在深海发现这种多细胞有机生物时，他们曾猜想这些生物是从富氧水域沉降而来的。

What genetic change allowed multicellular animals to come into existence remains obscure .

什么样的遗传突变产生了多细胞的动物还不清楚。