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: Chordates have a complete digestive system and a closed circulatory system. 
Sentence2: animals with jaws have a complete digestive system and a closed circulatory system.
[EX A]: circulatory

[EX Q]: Sentence1: Chordates have a complete digestive system and a closed circulatory system. 
Sentence2: All chordates are vertebrates.
[EX A]: Chordates

[EX Q]: Sentence1: Stimuli are detected by sensory nerve cells. 
Sentence2: changes in the environment are detected by sensory nerve cells.
[EX A]:
cells