Let's first trying to define and understand BIOS and Kernel.
BIOS stands for "Basic Input/Output System", in old machines, the firmware was known as the BIOS, but more modern systems use UEFI (The Unified Extensible Firmware Interface) now, which is faster and more general and makes better use of facilities in contemporary processors.
The one program running at all times on the computer. It is the core of a computer's OS, with complete control over basically everything in the system. Typically, it is responsible for memory management, process management and disk storage management. It is the middle layer between system hardware and applications.
BIOS vs Kernel
For a computer to start running, for instance, when you power it up, it needs to have an initial program to run. This little simple "initial program" is also called "bootstrap program", typically is stored within the computer hardware in ROM (Read-only memory) or EEPROM (Electrically erasable programmable read-only memory), known by the general term firmware, now if you connect the BIOS definition we defined earlier, you should have a good understanding of what BIOS is. The firmware (BIOS) initializes all aspects of the system, from CPU registers to device controllers to memory contents. Then it locates the kernel and load it into a protected area of memory for running.
Hope my answer helps.