What is the difference between a source and a mouth

¿cual es mas alta en baja california,la migracion o la inmigracion?

In the diagram below dab and dac are adjacent angles

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