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: Polygenic inheritance Polygenic traits are controlled by an unknown number of genes. 
Sentence2: Skin color is inherited from a number of genes.

SOLUTION: genes

PROBLEM: Sentence1: Interstellar space contains a plasma. 
Sentence2: interstellar space contains electrons, atoms, and stars.

SOLUTION: Interstellar

PROBLEM: Sentence1: Amphibians have permeable skin that easily absorbs substances from the environment. 
Sentence2: Amphibians begin their lives in the water.

SOLUTION:
Amphibians