>>/9178/
https://httpd.apache.org/docs/2.4/mpm.html
See MPMDefaults section. 2.4 is current version. It's one of several based on criteria, and is generally the default, but that's not even relevant.

As far as knowing what I mean...
so Listen just specifies how much backlog you can set on a socket object

https://linux.die.net/man/2/listen

>   listen() marks the socket referred to by sockfd as a passive socket, that is, as a socket that will be used to accept incoming connection requests using accept(2). 

There are other things there, as well.

This should have led you to the answer in accept:

https://linux.die.net/man/2/accept
>  The accept() system call is used with connection-based socket types (SOCK_STREAM, SOCK_SEQPACKET). It extracts the first connection request on the queue of pending connections for the listening socket, sockfd, creates a new connected socket, and returns a new file descriptor referring to that socket. The newly created socket is not in the listening state. The original socket sockfd is unaffected by this call. 

This double-confirms. First: it is a system call. Single-threaded, single process.

Second, it returns an fd.
Fds are relative to only a single process.

Multiple threads could accept sockets, I guess... but why? Then you just lose cache coheriency and  you have to invent a complicated thing to switch them around so only the first doesn't get everything.

You also don't get control over anything the web server is doing in regards to other calls to use... not that those calls are even applicable at all to binding a socket and handling a connection. Gotta have that fd.

This is a kinda fun topic.