Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

[Q]: Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: If an object is made of a drug, then that object has the properties of that drug.
[A]: made


[Q]: Sentence1: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past. 
Sentence2: if remains of prehistoric life are found in a place then that place used to be covered by water.
[A]: be


[Q]: Sentence1: Lancelet larvae are free-swimming. 
Sentence2: some larvae lack a hardened backbone.
[A]:
larvae