TASK DEFINITION: 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.
PROBLEM: Sentence1: DNA is made up of nucleotides. 
Sentence2: Mutations can change the structure of DNA.

SOLUTION: DNA

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

SOLUTION: sharks

PROBLEM: Sentence1: Some animals sweat, some pant, some lick. 
Sentence2: An animal panting has decreased body water.

SOLUTION:
animals