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.

Q: Sentence1: Chordates have a complete digestive system and a closed circulatory system. 
Sentence2: animals with jaws have a complete digestive system and a closed circulatory system.

A: circulatory
****
Q: Sentence1: Very often their only metal object in the house is a cooking pot or a knife. 
Sentence2: sharpening a knife causes it to change shape.

A: knife
****
Q: Sentence1: Female gametophytes produce eggs inside the ovaries of flowers. 
Sentence2: Female gametophytes produce eggs inside the part of the flower where the fruit will eventually develop.

A:
Female
****