why the partition doesn't start from 0 (Screen shot is attached for better understanding), where is Partition 0?

Hi All,

I have a question about Disk Management in the windows environment. its a very strange question just need the answer for my Knowledge.

when we connect HDD, its always start disk with 0 and when we create partition, it start from 1.

why the partition doesn't start from 0, where is Partition 0?

Waiting for your respond (if found any article please share the link).

Thanks,