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.

Sentence1: Viruses are usually considered to be nonliving. 
Sentence2: Viruses are usually acquired from contact with infected animals.
Viruses

Sentence1: Passive immunity lasts only as long as the antibodies survive in body fluids. 
Sentence2: A pregnant woman will pass antibodies to the fetus.
antibodies

Sentence1: Roundworms reproduce sexually. 
Sentence2: Sexual reproduction is the combination of egg and sperm to form larvae.

sexually