For credible research materials, the best options would be sites ending in .gov and .edu.
- .gov websites are official government sites that provide accurate information, data, and resources on various topics.
- .edu websites are associated with educational institutions, such as universities and colleges, which often publish research papers, studies, and other academic content.
While .org sites can also be credible, they are often associated with non-profit organizations and may have biases or specific agendas. Meanwhile, .com sites can vary widely in credibility and often include commercial entities. Therefore, when conducting research, it's generally safest to prioritize .gov and .edu sites for reliable information.