It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
When you do research for your assignments or are doing some studying, you will look at various information sources. You need to think critically not just about how the sources agree or disagree with your arguments, but also whether you should be using these sources in the first place. When it comes to information sources, quality is better than quantity. If you are using sources to support your argument, then those sources should be credible. You might lose marks by using poor quality or inappropriate sources, so it's important make sure you assess your sources before you using them.
This is especially true for using web pages as information sources. The web is great: it is accessible, convenient and provides information on anything and everything. However, the web is that is so large and contains so much stuff, that it's often difficult to assess and evaluate that information; anyone can create a website and publish anything on the web, no matter how false, biased or just plain ridiculous.
You don't have to be any kind of expert to be able to figure out whether a web page can be trusted, and same goes for other information sources, such as books and articles. These pages will help you assess the quality of your sources and whether they can be trusted. The pages concentrate on evaluating websites, but you can use the same methods to think about other sources too.