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: Capillaries are microscopic vessels. 
Sentence2: Lymph is a fluid that leaks out of microscopic vessels into spaces between cells.

SOLUTION: microscopic

PROBLEM: Sentence1: Plants exhibit phototropism, or growing toward a light source. 
Sentence2: Phototropism means growing toward the energy of light.

SOLUTION: phototropism

PROBLEM: Sentence1: More carbon in the atmosphere means atmospheric warming. 
Sentence2: Burning fossil fuels warms the atmosphere.

SOLUTION:
atmospheric