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: Plants use unsaturated fatty acids to store energy. 
Sentence2: Plants and fish contain fatty acids.
Plants

Sentence1: All sharks are predators. 
Sentence2: hiding can be used for avoiding sharks.
sharks

Sentence1: a scale is used for measuring weight. 
Sentence2: An object's weight is the force of gravity on that object.

weight