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: All frogs are amphibians. 
Sentence2: frogs have permeable skin that easily absorbs substances from the environment.

SOLUTION: frogs

PROBLEM: Sentence1: Warm temperatures have helped plant growth and sizing. 
Sentence2: a greenhouse helps  plant growth.

SOLUTION: growth

PROBLEM: Sentence1: ultraviolet light causes sunburn. 
Sentence2: Sunburn risk is higher at elevation.

SOLUTION:
sunburn