1. Kernel: The kernel is like the brain of a computer operating system. It handles important tasks, such as managing memory, running programs, and talking to hardware. Basically kernel is the core of an operating system.

2.Linux: Linux is an operating system, like Windows or macOS. It is built using the Linux kernel as its core.

3.Linux is generally secure but  it's not completely immune to malware. Being careful, updating the system, and using good security practices can help protect against threats. So claiming to be entirely immune to malware would be inaccurate.