My boss asked for a primary source of customer feedback on a new product. I showed him some of our customer tweets are they primary sources ?

The earth is composed of three different chemical layers: core, mantle and crust. the formation of these layers was from a process called

When reading a textbook blank. a) it’s safe to assume that the ingot is not biased b) you should watch for fallacies in information and author bias c) you should fact check everything you read d) it is understood that academic sources are not biased

What does the plate tectonic theroy describe?