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.

[EX Q]: Sentence1: Ground tissue makes up most of the interior of a plant. 
Sentence2: ground tissue makes up most of the interior of a dandelion.
[EX A]: Ground

[EX Q]: Sentence1: sharpening an object causes that object to change shape. 
Sentence2: sharpening a knife causes it to change shape.
[EX A]: causes

[EX Q]: Sentence1: Lancelet larvae are free-swimming. 
Sentence2: After lancelet eggs are fertilized, they develop so that they can navigate in the water themselves.
[EX A]:
Lancelet