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: when a river floods , that river deposits soil in flood plains. 
Sentence2: when a river floods, it deposits soil in generally marshy areas.
[EX A]: deposits

[EX Q]: Sentence1: Mollusks are invertebrates such as the common snail. 
Sentence2: snails have no backbone.
[EX A]: snail

[EX Q]: Sentence1: Fertilization occurs when sperm swim to an egg inside an archegonium. 
Sentence2: sperm nuclei enter the egg.
[EX A]:
egg