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 Input:
Sentence1: People of all ages and activity levels perspire or sweat. 
Sentence2: Perspiration reduces body heat.

Ex Output:
perspire


Ex Input:
Sentence1: faulting of rock in Earth 's crust causes earthquakes. 
Sentence2: fault movement forms earthquakes.

Ex Output:
earthquakes


Ex Input:
Sentence1: Animals that survive by catching prey or escaping predators have special adaptations for running. 
Sentence2: predators eat prey.

Ex Output:

predators