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: Plants that shed their leaves seasonally each year are called deciduous plants. 
Sentence2: vines shed their leaves seasonally each year.
each

Sentence1: friction causes the temperature of an object to increase. 
Sentence2: internal combustion engines get hot.
temperature

Sentence1: Limestone is a type of sedimentary rock. 
Sentence2: limestone is formed by deposition.

Limestone