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.

Input: Consider Input: Sentence1: if a habitat can no longer support animals then those animals will move to another area. 
Sentence2: Each species of animal is unique.

Output: animals


Input: Consider Input: Sentence1: Fission is a type of reproduction, but a baby is the result of sexual reproduction. 
Sentence2: the fallopian tubes are used to make babies.

Output: baby


Input: Consider Input: Sentence1: Sexual union is for pleasure and closeness and for procreation. 
Sentence2: Sperm are deposited in the vagina during procreation.


Output: procreation