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: a stopwatch is used to measure time. 
Sentence2: Time can be measured with a clock or watch.
[A]: measure


[Q]: Sentence1: plant requires seed dispersal for reproduction. 
Sentence2: plants are pollinated by birds.
[A]: plant


[Q]: Sentence1: Immunity results from immunization. 
Sentence2: The ability of an organism to not be susceptible to a certain disease can result from vaccines.
[A]:
results