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.

[EX Q]: Sentence1: Flatworms Flatworms or Platyhelminthes include flukes, tapeworms, and turbellarians. 
Sentence2: Tapeworms belong to the phylum Platyhelminthes.
[EX A]: tapeworms

[EX Q]: Sentence1: cold fronts cause thunderstorms as they pass by. 
Sentence2: Cold fronts cause lightning.
[EX A]: cold

[EX Q]: Sentence1: an aquatic animal requires great amounts of water to survive. 
Sentence2: Survival is about making a living.
[EX A]:
survive