instruction:
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.
question:
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.
answer:
monogamous


question:
Sentence1: Muscles can only contract. 
Sentence2: Contraction is a type of movement.
answer:
contract


question:
Sentence1: Cells are the microscopic building blocks of organisms. 
Sentence2: cells are the microscopic building blocks of plants.
answer:

Cells