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: skin is used for protecting the body from harmful substances. 
Sentence2: Acids are harmful to tissue.
harmful

Sentence1: Silica sand is primarily mined from sandstone deposits. 
Sentence2: erosion forms silica sand.
Silica

Sentence1: Pathogenic organisms that live inside cells have a neat adaptation. 
Sentence2: Viruses are pathogenic organisms.

Pathogenic