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: Viruses are parasites of cells.
Sentence2: Populations of viruses do not grow through division because they are parasites.

SOLUTION: are

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: Fossils are the remains of prehistoric life.

SOLUTION: fossils

PROBLEM: Sentence1: darkness has a negative impact on photosynthesis.
Sentence2: darkness has an impact on the energy the sun releases.

SOLUTION:
darkness