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.

[EX Q]: Sentence1: when a hemisphere is tilted away from the sun , that hemisphere receives less direct sunlight. 
Sentence2: Sunlight is delivered in small packets of energy called photons.
[EX A]: sunlight

[EX Q]: Sentence1: Streams may start with runoff or water seeping out of a spring. 
Sentence2: Most water comes from precipitation.
[EX A]: water

[EX Q]: Sentence1: DNA contains genetic instructions for proteins, and RNA helps assemble the proteins. 
Sentence2: DNA is the genetic material responsible for heredity.
[EX A]:
DNA