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: camouflage is used for protection by prey against predators. 
Sentence2: blending is used for protection.

SOLUTION: protection

PROBLEM: Sentence1: Echinoderms lack respiratory and excretory systems. 
Sentence2: echinoids lack a respiratory system.

SOLUTION: respiratory

PROBLEM: Sentence1: a pan is used for cooking food by heating food in it on a stove. 
Sentence2: Chicken and potatoes can be cooked in a pan on the stove.

SOLUTION:
cooking