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 requires time.
[EX A]: healing

[EX Q]: Sentence1: Lymphocytes are the key cells involved in the immune response. 
Sentence2: The key cells involved in the immune response produce antibodies.
[EX A]: cells

[EX Q]: Sentence1: Soil can be depleted of nutrients. 
Sentence2: Potassium carbonate is a valuable nutrient for plants.
[EX A]:
nutrients