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

A: Herbs
****
Q: Sentence1: the force of water against the seed coat causes a root to emerge from a seed. 
Sentence2: Germination depends on the seed coat.

A: coat
****
Q: Sentence1: a greenhouse is used to protect plants from the cold. 
Sentence2: Plants are grown where they are protected from the cold.

A:
cold
****