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: mineral graphite is used for making pencil lead. 
Sentence2: Diamond and graphite are made of carbon.
graphite

Sentence1: After about a week the larvae leave the nodules and continue to develop into adult worms. 
Sentence2: larvae leave the nodules and continue to transform until having reproductive organs.
larvae

Sentence1: All echinoderms are marine and benthic. 
Sentence2: marine and benthic creatures lack respiratory and excretory systems.

benthic