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: DNA is made up of nucleotides. 
Sentence2: Mutations can change the structure of DNA.
DNA

Sentence1: Chordates have a complete digestive system and a closed circulatory system. 
Sentence2: All chordates are vertebrates.
Chordates

Sentence1: Ethanol is produced by alcoholic fermentation of the glucose in corn or other plants. 
Sentence2: Glucose, a type of sugar, is the body's fuel.

glucose