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: the force of water against the seed coat causes a root to emerge from a seed. 
Sentence2: Germination depends on the seed coat.
Example Output: coat

Example Input: Sentence1: igneous rocks are formed from magma cooling. 
Sentence2: magma solidifies into igneous rocks.
Example Output: magma

Example Input: Sentence1: sugar causes food to taste sweet. 
Sentence2: Sugar causes tooth decay and unhealthy gums.
Example Output:
causes