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: Limestone caves displaying stalactites. 
Sentence2: Limestone caves are formed by depositions.

A: Limestone
****
Q: Sentence1: Instead, the body is covered with a protective shell of bony armor. 
Sentence2: Most mollusks have protective of bony armor.

A: armor
****
Q: Sentence1: braking can cause skidding. 
Sentence2: Brakes are also helpful to stop or slow down for turns.

A:
braking
****