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.
--------
Question: Sentence1: Amphibians are the first true tetrapods, or vertebrates with four limbs. 
Sentence2: Frogs are classified as amphibians.

Answer: Amphibians


Question: Sentence1: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past. 
Sentence2: if remains of prehistoric life are found in a place then that place used to be covered by water.

Answer: be


Question: Sentence1: Cover Crops Cover Crops usually are grown to prevent soil loss from wind and water erosion. 
Sentence2: Growing crops is done to prevent soil erosion.

Answer:
Crops