TASK DEFINITION: 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.
PROBLEM: Sentence1: Mammalian teeth are important for digestion. 
Sentence2: bats' teeth are important for digestion.

SOLUTION: digestion

PROBLEM: Sentence1: Insect wings are attached to the dorsal side of their thorax. 
Sentence2: wings are attached to the dorsal side of the insect.

SOLUTION: dorsal

PROBLEM: Sentence1: astronauts require preserved food for extended flights. 
Sentence2: A scientist who is a space explorer requires preserved food for extended flights.

SOLUTION:
extended