if userland in asm, no need for libc?

[iam at sdf.org]

in continuum to my previous mail about libc;
if the whole of userland and various other toolkits were written
in assembly language, would there be no need for libc, that is
if "c" were not needed to be supported at all?
do assembly language programs have the capacity to make kernel
calls directly? i.e., without going through any libraries?
pardon my naive questions, i don't have a background in computer
science nor enough self-training.