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.

Sentence1: Nitrogen is found in proteins, nucleic acids, and chlorophyll. 
Sentence2: Nitrogen, as a gas, is colorless, odorless, and a generally inert element.
Nitrogen

Sentence1: Streams may start with runoff or water seeping out of a spring. 
Sentence2: streams may start with runoff or h2o seeping out of a spring.
Streams

Sentence1: adding salt to a solid decreases the freezing point of that solid. 
Sentence2: Water sources can be frozen solid.

solid