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: An organism can gain energy by assimilation or absorption of food. 
Sentence2: Organisms require food for growth.
[EX A]: food

[EX Q]: Sentence1: threatening behavior by predators causes a porcupine to extend its quills. 
Sentence2: Fishers are predators that can eat porcupines.
[EX A]: predators

[EX Q]: Sentence1: a plant requires nutrients to grow. 
Sentence2: Fertilizers add nutrients to the soil.
[EX A]:
nutrients