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: All cells share some of the same structures and basic functions. 
Sentence2: Inside the cell is a structure called the nucleus.

SOLUTION: cells

PROBLEM: Sentence1: Speciation events are thus examples of macroevolution. 
Sentence2: Speciation events occur over geologic time above the level of the species.

SOLUTION: Speciation

PROBLEM: Sentence1: the ovaries are used in reproduction. 
Sentence2: Unlike most female animals, which have two functioning ovaries, the chicken usually has only one.

SOLUTION:
ovaries