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: Mammals that are viviparous are called therian mammals. 
Sentence2: Mouse-sized viviparous mammals evolved by Jurassic times.

SOLUTION: Mammals

PROBLEM: Sentence1: the mass of an object causes the gravitational force exerted by that object. 
Sentence2: gravitational force accelerates objects.

SOLUTION: force

PROBLEM: Sentence1: a solution is formed by one substance being dissolved in another substance. 
Sentence2: An unsaturated solution is a dilute solution.

SOLUTION:
solution