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: Excretion is the process of removing wastes and excess water from the body. 
Sentence2: parasites remove waste from their bodies.

SOLUTION: wastes

PROBLEM: Sentence1: Mammalian teeth are important for digestion. 
Sentence2: bats' teeth are important for digestion.

SOLUTION: digestion

PROBLEM: Sentence1: the fallopian tubes are used in reproduction. 
Sentence2: Fallopian tubes are used in producing offspring.

SOLUTION:
fallopian