Arsenic is present in the environment as a naturally occurring substance or as a result of contamination from human activity. It is found in water, air, food, and soil in organic and inorganic forms.
Latent Semantic Analysis (LSA), sometimes referred to as Latent Semantic Indexing (LSI), is an information modeling and analysis technology. It enables you to organize and examine large collections of information based on meaning (semantics), not just matching the words or items being used.
Talk about airplanes! At last count, there are 39 (and growing) FAA certificated S-LSA (special light sport aircraft). These are factory-built ready to fly airplanes. If you can't afford a factory-built LSA, consider buying an E-LSA kit (experimental LSA - up to 99% complete).