1.
The kernel acts as a bridge between the software and the hardware of a computer. It is responsible for managing the system's memory, processor, input/output devices, and other essential resources. The kernel provides services such as process management, memory management, device drivers, file system access, and security mechanisms.

2.
Linux is a kernel, not an operating system itself. An operating system consists of multiple components, including the kernel, system utilities, libraries, graphical interfaces, and application software. When people commonly talk about "Linux," they are often referring to a complete operating system distribution that uses the Linux kernel along with a variety of other software packages to create a functional and usable system.


3.
Linux has certain security advantages over other operating systems, it is not immune to malware. No operating system is completely immune to malware, as attackers are constantly finding new vulnerabilities and developing new methods to compromise systems.  Linux's design, open-source nature, and strong permission model make it generally more secure than some other operating systems like Windows. However, its security is not solely dependent on the kernel; it also relies on the practices of the user, system administrators, and the overall security of the applications and services running on the system.