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: friction causes the temperature of an object to increase. 
Sentence2: internal combustion engines get hot.
temperature

Sentence1: Enveloped viruses make their own membranes. 
Sentence2: Some viruses make their own membranes.
make

Sentence1: Some mollusks are nearly microscopic. 
Sentence2: Invisible to the naked eye, the damage is detectable by microscope.

microscopic