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: Herbs are medicines and aids. 
Sentence2: herbs are used for curing people when they are sick.
Herbs

Sentence1: If there is enough moisture in the clouds, rain is produced. 
Sentence2: Clouds lacking water reduces rainfall.
clouds

Sentence1: Bamboos are vigorous, rugged plants. 
Sentence2: bamboo exhibits phototropism.

Bamboos