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: a wildfire changes an ecosystem drastically. 
Sentence2: Forest fires change an ecosystem drastically.
[EX A]: changes

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

[EX Q]: Sentence1: Blood pH may become unbalanced if the rate of breathing is too fast or too slow. 
Sentence2: Rate of breathing being too fast or too slow can lead to alkalosis.
[EX A]:
breathing