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.

Sentence1: Flies are insects with two wings. 
Sentence2: Flies are arthropods with two wings.
Flies

Sentence1: Arthropods Arthropods have jointed segmented exoskeletons. 
Sentence2: Insects have jointed segmented exoskeletons.
exoskeletons

Sentence1: Annelids are worms such as the familiar earthworm. 
Sentence2: Earthworms have some of the fastest reflexes in the animal kingdom.

earthworm