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: 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: a pulley is used for lifting objects. 
Sentence2: Resistance exercises are weight-lifting exercises.
[EX A]: lifting

[EX Q]: Sentence1: zinc has a positive impact on the healing of wounds. 
Sentence2: vitamin c is beneficial to wounds.
[EX A]:
wounds

