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: Some mollusks are nearly microscopic. 
Sentence2: Some squids are nearly microscopic.

A: Some
****
Q: Sentence1: an animal requires warmth for survival. 
Sentence2: Light and heat and warmth are basic necessities for survival.

A: warmth
****
Q: Sentence1: electricity sometimes is used for heating buildings. 
Sentence2: Resistors are used to convert energy into heat to heat buildings.

A:
buildings
****