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: Arthropods Arthropods have jointed segmented exoskeletons. 
Sentence2: Insects have jointed segmented exoskeletons.
Example Output: exoskeletons

Example Input: Sentence1: Cells are the microscopic building blocks of organisms. 
Sentence2: proteins are the building blocks of organisms.
Example Output: organisms

Example Input: Sentence1: Kiwifruit flowers are pollinated by bees. 
Sentence2: Petals attract bees to flowers.
Example Output:
bees