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: Ice is frozen water. 
Sentence2: ice expands.
Ice

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

Sentence1: Coal forms from dead plants, compacted. 
Sentence2: dead plants can generate heat.

dead