Parts of it are. The kernel is derived from a Mach microkernel (an experimental kernel in the 80s, which was theoretically supposed to allow different OS personalities to coexist in the same system, sharing resources; macOS’ Darwin/XNU kernel doesn’t implement this capability in full, but you do get the Mach Ports interprocess communication mechanism, and a BSD UNIX personality permanently attached).
Yes, and the FreeBSD kernel is also derived from it, but they both formed out of that. One to form NeXT mach and the other Net, which forked to NetBSD and FreeBSD. But macOS Mach isn’t derived from the FreeBSD fork.
It’s derived from BSD 4.3, which predates and is one of the ancestors of FreeBSD
Parts of it are. The kernel is derived from a Mach microkernel (an experimental kernel in the 80s, which was theoretically supposed to allow different OS personalities to coexist in the same system, sharing resources; macOS’ Darwin/XNU kernel doesn’t implement this capability in full, but you do get the Mach Ports interprocess communication mechanism, and a BSD UNIX personality permanently attached).
Yes, and the FreeBSD kernel is also derived from it, but they both formed out of that. One to form NeXT mach and the other Net, which forked to NetBSD and FreeBSD. But macOS Mach isn’t derived from the FreeBSD fork.