Final answer:
A domain, like '.edu', '.gov', or '.org', uniquely identifies a website's affiliation on the web and can indicate its trustworthiness. Educational, governmental, and nonprofit websites are often considered more reliable than commercial sites. When available, using a DOI for citations is preferable as it remains constant.
Step-by-step explanation:
A domain, such as '.edu', '.gov', or '.org', uniquely identifies a site and a brand on the web. The domain indicates the nature of the affiliation of the website. For instance:
If its domain includes .edu, it is affiliated with a college or university.
If it includes .gov, it is affiliated with the federal government.
And if it includes .org, it is affiliated with a nonprofit organization.
These types of domains are generally more trustworthy sources of information. In contrast, domains ending in .com are commercial or business websites. When citing a page or work on a website, if the source is listed with a DOI (Digital Object Identifier), it's better to use that instead of a URL since a DOI remains constant even if the URL changes.