Binary programs are executed on the CPU but the program file is an archive with sections, and only one of them is the program, usually, while the others are all metadata. The CPU isn't capable of understanding the program file at all. Linux has to establish the conditions under which the program runs, that means at a minimum establishing the address space in which the program counter lies then jumping to that address. The instructions for how to do that are in the metadata sections of the ELF executable.
not too bad explain, though the 'usually' might be clarified that an ELF file 'can have sections marked as executable' (tho ofc i get not wanting to get into segment flags :p) and also a program is cobbeled together potentially from many of these ELF files. in most cases the single file is useless. (most cases as in binaries provided by a standard linux distro, now 'producible binaries')
