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: Adaptation traits contribute to individual fitness and to the evolution of animal genetic resources. 
Sentence2: Behaviors can improve the evolution of animal genetic resources.
animal

Sentence1: Centrioles come in pairs. 
Sentence2: Something that comes in pairs are organelles involved in cell division.
come

Sentence1: Over medium heat, scramble the eggs. 
Sentence2: Scrambled eggs are an example of a chemical reaction.

eggs