There are some really good resources out there that explain the diffences between Indica and Sativa. Here's a good one from Mary Jane's Diary that outlines 9 indicators to look for that will help you identify the differences between these two types of strains. 

A cannabis extract is an oil that is made by extracting the cannabis plant's chemical compounds including THC and CBD as a concentrate. This is achieved through a variety of extraction processes and solvents, the most common being butane. Leafly provides a good overview of cannabis oils, extracts, and shatter.

Cannabis can be grown chemical free, but because the plant is still considered illegal by the federal government, there is no certification process to get organic certification. 

There are a couple services who do test cannibis products for "organically grown" conditions including Clean Green Certified. All of the products at Rooted Northwest are clean, green certified.
For more information, check out the Clean Green Certified website.