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: All oaks are trees. 
Sentence2: Cutting down oaks has a negative impact on an ecosystem.
[A]: oaks


[Q]: Sentence1: Landslides Seismic vibration is a common triggering mechanism for landslides. 
Sentence2: Erosion can cause seismic vibrations which are triggering mechanisms.
[A]: Seismic


[Q]: Sentence1: Pollen consists of tiny grains that are the male gametes of plants. 
Sentence2: Flowers are the sex organs of certain plants and hold the male and female gamete producing systems.
[A]:
gametes