What are the differences between those three API

I already figured out how to call the API. and There's a csv for 'get' parameter. This csv record more than 40000 specific category of population. But I don't get the differences between those three APIs

https://api.census.gov/data/2020/acs/acs5/subject/examples.html

https://api.census.gov/data/2020/acs/acs5/profile/examples.html

https://api.census.gov/data/2020/acs/acs5/examples.html.
