In the sciences, there is a strong focus on acknowledging sources through citation. It recognizes the authors of the information we use and helps to show how we build on that information. It also helps us provide others with the ability to find those resources and read more about the topic!
Citing others' work helps us to join that scholarly conversation and start to not only see the relationships between different ideas and works, but also build relationships with these researchers, sources, and ideas ourselves.
APA is a common citation style in the sciences but there are many others. The important thing is to include all the information that someone else would need to find that resource themselves, or in the case of a resource that is not findable, like an interview or presentation, to give the 'author' recognition for their contribution.