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: First, the bottle is calibrated with a graduated cylinder. 
Sentence2: calibration is performed with a cylinder.
[EX A]: calibrated

[EX Q]: Sentence1: Ferns are vascular plants. 
Sentence2: when a fern grows, its size of leaves may increase.
[EX A]: Ferns

[EX Q]: Sentence1: Playing is just one of many ways that mammals and other animals learn how to behave. 
Sentence2: Cats are Mammals that Shed Dogs are Mammals that Wag their tails.
[EX A]:
mammals