TASK DEFINITION: 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.
PROBLEM: Sentence1: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past.
Sentence2: Common fossils include plant fossils like ferns.

SOLUTION: plant

PROBLEM: Sentence1: Generally, pheromones are volatile substances.
Sentence2: Male dogs use volatile substances in urine to mark their territory.

SOLUTION: substances

PROBLEM: Sentence1: Typically, the liquid is water.
Sentence2: a cactus stem is used for storing liquid.

SOLUTION:
liquid