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recycle – v. to reuse something that has been used before often in another way
enzyme – n. a chemical substance produced by living cells that makes particular chemical reactions happen in animals and plants
precipitation – n. rain or snow falling to the ground
three-dimensional – adj. appearing to have length, depth and width
galaxy – n. a large group of stars from the same universe
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 that lived in ancient times
unit – n. a single thing or a separate part of something larger
timespan – n. a period of time within which something happens, or a period between two events
