PLZ HELP ASAP What are the organisms still alive that display some of the earliest vertebrate evolutionary characteristics?

Hag Fish and Lamprey
Vertebrates are the organism which posses a vertibral column(aka the spine or back bone structure), while the earliest had a head they lacked a spine and jaw, these jawless vertebrae lived 500-600 million years ago. they are the ancestors of bony fish which in time became amphibians and other groups of animals

Resistance than a bicycle? i'm not entirely sure