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.

[EX Q]: Sentence1: healing requires rest. 
Sentence2: Healing and cell regeneration follows.
[EX A]: healing

[EX Q]: Sentence1: Passive immunity lasts only as long as the antibodies survive in body fluids. 
Sentence2: A pregnant woman will pass antibodies to the fetus.
[EX A]: antibodies

[EX Q]: Sentence1: burning fossil fuels increases the carbon in the atmosphere. 
Sentence2: The atmosphere is mostly carbon dioxide .
[EX A]:
atmosphere