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: Among monogamous species of birds and mammals, both parents often care for their offspring. 
Sentence2: The period of parental care after birth for manogamous species are handled by both parents.

A: monogamous
****
Q: Sentence1: Bound and free ribosomes are structurally identical and interchangeable. 
Sentence2: Bound and free structures are in the cytoplasm where proteins are made.

A: Bound
****
Q: Sentence1: Alternation of generations allows for both asexual and sexual reproduction. 
Sentence2: Alternation of generations allows for both vegetative and sexual reproduction.

A:
Alternation
****