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.

Example Input: Sentence1: Blood pH may become unbalanced if the rate of breathing is too fast or too slow. 
Sentence2: If Someone Is Hyperventilating Hyperventilation is caused by breathing too deeply, too fast.
Example Output: breathing

Example Input: Sentence1: Aquatic animals are adapted to living within certain salinity ranges. 
Sentence2: Animals adapted to living within certain salinity ranges require great amounts of water to survive.
Example Output: adapted

Example Input: Sentence1: Biological evolution is slow, while corporate evolution is fast. 
Sentence2: The change in the characteristics of living things over time is slow.
Example Output:
slow