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: Water erosion has similar consequences as wind erosion. 
Sentence2: exposure to water can cause erosion.

SOLUTION: Water

PROBLEM: Sentence1: threatening behavior by predators causes a porcupine to extend its quills. 
Sentence2: Fishers are one of the few specialized predators on porcupines.

SOLUTION: predators

PROBLEM: Sentence1: Fission takes place when an animal divides into two parts. 
Sentence2: Asexual reproduction is by fragmentation, budding, or fission.

SOLUTION:
Fission