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: Soil Erosion Soil erosion is a natural process. 
Sentence2: wind and rain is a natural process.
[A]: natural


[Q]: Sentence1: Most bryophytes are small. 
Sentence2: Most in the same group as mosses are small.
[A]: small


[Q]: Sentence1: medicine is used for curing people when they are sick. 
Sentence2: Herbs are medicines and aids.
[A]:
medicine