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: cell division often causes growth. 
Sentence2: Mitosis is cell division.

SOLUTION: cell

PROBLEM: Sentence1: Dams are very damaging to rivers. 
Sentence2: Creating a lake can be very damaging to rivers.

SOLUTION: damaging

PROBLEM: Sentence1: Birds are endothermic tetrapod vertebrates. 
Sentence2: hooded vultures are endothermic tetrapod vertebrates.

SOLUTION:
endothermic