Basic facts, like those found in an encyclopedia that gives you a general understanding of a topic.
Sample question: Hey Google, what causes deep vein thrombosis?
Specific information that informs clinical decisions for specific patients or populations.
Sample question: Could a patient with deep vein thrombosis, who is taking warfarin, be adversely affected by adding more vitamin k to his diet?
You can see these questions are very different. To locate background information on a topic, you may wish to consult encyclopedias, dictionaries, and textbooks. To locate foreground information, you will need to locate evidence-based, peer-reviewed journal articles.
P: Patient or population
I: Intervention or treatment
C: Comparison – what is the other alternative?
O: Outcome: what result do you expect or wish to measure?
(e.g.) Which treatment for asthma is more likely to be beneficial to children: acupuncture or herbal remedies? Are these CAM treatments more effective than traditional treatments like inhaled corticosteroids?