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: Faster metabolism means more calories consumed, and usually, weight loss. 
Sentence2: mammals generate heat by consuming calories.
[EX A]: calories

[EX Q]: Sentence1: Stress is the applied force, strain is the change in shape. 
Sentence2: Paper is crumbled when stress and strain is applied in order to change the shape.
[EX A]: Stress

[EX Q]: Sentence1: Fish have a two-chambered heart while mammals and birds have four chambered hearts. 
Sentence2: Mammals and fish have different circulatory systems.
[EX A]:
mammals