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: Antigens are proteins foreign to the body. 
Sentence2: antigens are proteins.
proteins

Sentence1: Endospores are commonly found in soil and water. 
Sentence2: Dirt is really misplaced soil.
soil

Sentence1: Sandstones are another type of sedimentary rocks used in buildings. 
Sentence2: sandstones are formed by deposition.

Sandstones