Do nginx.conf files in sites-available inherit from /etc/nginx/nginx.conf

At the moment I am not creating an http block in my custom nginx.conf files that I am placing in sites-available.

If I do not create an http block in my files, does my file inherit from nginx.conf location in /etc/nginx/nginx.conf

I noticed at the bottom of the /etc/nginx/nginx.conf that this file includes the files that are in in sites-enabled, so I am guessing it does? If this is the case, what happens if I declare an http block in my app specific nginx.conf file? Will it ignore the default configuration from /etc/nginx/nginx.conf?