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: rain causes erosion. 
Sentence2: Soil Erosion Soil erosion is what happens when soil is washed or blown away.

SOLUTION: erosion

PROBLEM: Sentence1: Homogeneous mixtures are called solutions. 
Sentence2: A homogenous mixture is formed when one substance dissolves in another.

SOLUTION: Homogeneous

PROBLEM: Sentence1: Softwoods, on the other hand, are gymnosperms . 
Sentence2: Softwoods are vascular plants that produce seeds in cones.

SOLUTION:
Softwoods