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: adding salt to a solid decreases the freezing point of that solid. 
Sentence2: Water density decreases with temperature and increases with salt content.

SOLUTION: decreases

PROBLEM: Sentence1: plant reproduction requires pollination. 
Sentence2: Plant reproduction requires insects and hummingbirds.

SOLUTION: plant

PROBLEM: Sentence1: if an object reflects light toward the eye then that object can be seen. 
Sentence2: Light is made up of particles called photons.

SOLUTION:
light