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: Habitat destruction is the primary cause of extinction or threat of extinction for all animals.
Sentence2: building housing developments may cause extinction.

Ex Output:
extinction

Ex Input:
Sentence1: Male dogs use pheromones in urine to mark their territory.
Sentence2: Pheromones are hormones that are thought to stimulate, through smell, sexual reactions in animals.

Ex Output:
pheromones

Ex Input:
Sentence1: Balanced eating is a way of eating that promotes good health.
Sentence2: Healthy eating is all about motivation, balance, and flexibility.

Ex Output:
Balanced