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.

Q: Sentence1: Very often their only metal object in the house is a cooking pot or a knife. 
Sentence2: sharpening a knife causes it to change shape.

A: knife
****
Q: Sentence1: Earthquakes cause massive damage. 
Sentence2: tectonic plates being pushed together causes massive damage.

A: damage
****
Q: Sentence1: Each organism arises through reproduction-the production of offspring by one or more parents. 
Sentence2: Fallopian tubes are used in the process of offspring production.

A:
offspring
****