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: Blood type is important for medical reasons. 
Sentence2: Type O is important for medical reasons.

A: important
****
Q: Sentence1: a wildfire changes an ecosystem drastically. 
Sentence2: Forest fires change an ecosystem drastically.

A: changes
****
Q: Sentence1: the mass of a planet causes the pull of gravity on that planet. 
Sentence2: Earth's mass causes the pull of gravity.

A:
causes
****