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: high mountains with well-rounded peaks can be formed by collision of crustal plates. 
Sentence2: high mountains with well-rounded peaks can be formed by collision of plate tectonics.

A: collision
****
Q: Sentence1: Carpools and vanpools can save time. 
Sentence2: vanpools decrease the amount of cars used to travel to a place.

A: vanpools
****
Q: Sentence1: Consumers are heterotrophs that feed on tissues of other organisms. 
Sentence2: Heterotrophs may eat other organisms at more than one trophic level.

A:
heterotrophs
****