Ne.
Environment subsystems include POSIX, OS/2 and Windows subsystems. The Windows subsystem major components consists of the environment subsystem process (Csrss.exe which you can see tuning in the task manager), the kernel-mode device driver (Win32k.sys), subsystem DLLs (such as Kernel32.dll, Advapi32.dll, User32.dll, and Gdi32.dll) and Graphics device drivers.
https://blogs.msdn.microsoft.com/hanybarakat/2007/02/25/deeper-into-windows-architecture/