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: Many corals secrete an exoskeleton that builds up to become a coral reef. 
Sentence2: Good examples are Bubble coral, Elegance coral, Frogspawn and other Euphyllia corals.

SOLUTION: coral

PROBLEM: Sentence1: Boiling water can cause burns. 
Sentence2: heating water can cause burns.

SOLUTION: water

PROBLEM: Sentence1: Most echinoderms are sessile or sedentary marine forms with radial symmetry as adults. 
Sentence2: adult sponges are sedentary.

SOLUTION:
sedentary