VOA慢速英语:科学家发现世界上最古老的动物

millipede – n. a small creature that is like an insect and that has a long, thin body with many legs

fossilized – adj. having been changed into a fossil. A fossil is something (such as a leaf, skeleton, or footprint) that is from a plant or animal which lived in ancient times and that you can see in some rocks

worm – n. a long, thin animal that has a soft body with no legs or bones and that often lives in the ground

diversity – n. the quality or state of having many different forms, types, ideas, etc.

spine – n. the row of connected bones down the middle of the back