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: if humans disturb animals in a location then those animals will move to a different location. 
Sentence2: The human being is self-aware.
Example Output: humans

Example Input: Sentence1: Water is essential for all life on Earth. 
Sentence2: H2O is needed for all life on Eartth.
Example Output: Earth

Example Input: Sentence1: ice wedging is when ice causes rocks to crack by expanding in openings. 
Sentence2: Ice wedging is the most important form of mechanical weathering.
Example Output:
ice