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: mountains are formed by earthquakes. 
Sentence2: Mountains are formed by moving plates.

SOLUTION: are

PROBLEM: Sentence1: Macroevolution is more than repeated rounds of microevolution. 
Sentence2: evolution over geologic time above the level of the species is more than repeated rounds of microevolution.

SOLUTION: microevolution

PROBLEM: Sentence1: Growth is faster during infancy than it is during puberty. 
Sentence2: Adolescence is the period of transition between puberty and adulthood.

SOLUTION:
puberty