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: Endocrine glands include the pituitary, thyroid, parathyroid, adrenal, pineal and thymus glands. 
Sentence2: Some pituitary hormones can control the thyroid gland.
[EX A]: thyroid

[EX Q]: Sentence1: Flowers produce seeds for reproduction. 
Sentence2: flowers require dispersal for reproduction.
[EX A]: Flowers

[EX Q]: Sentence1: Bone is less flexible than cartilage but stronger. 
Sentence2: bone skeletons are less flexible than shark skeletons but stronger.
[EX A]:
Bone