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: Some pelycosaurs gave rise to a group of animals called therapsids. 
Sentence2: Like most other groups of synapsids, all pelycosaurs are now extinct.
[A]: pelycosaurs


[Q]: Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: items properties are the same as the materials the item is made of.
[A]: made


[Q]: Sentence1: Bacteria and archaea are the only prokaryotes. 
Sentence2: some prokaryotes are little known by scientists.
[A]:
prokaryotes