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: Pregnancy is the carrying of one or more offspring from fertilization until birth. 
Sentence2: An elephant carries their offspring from fertilization until birth, 22 months later.
fertilization

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

Sentence1: Soil can be depleted of nutrients. 
Sentence2: dirt can be depleted of nutrients.

be