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.
--------
Question: Sentence1: a flashlight converts chemical energy into light energy. 
Sentence2: Only as long as there are batteries in the flashlight, the flashlight will function.

Answer: flashlight


Question: Sentence1: hiding can be used for avoiding predators. 
Sentence2: Camouflage is used for avoiding predators.

Answer: avoiding


Question: Sentence1: Cells that divide uncontrollably may form a tumor, or abnormal mass of cells. 
Sentence2: Cancer is a malignant tumor.

Answer:
tumor