Question

In wich vertebrate heart does not pump oxygenated blood to different parts of the body

Answer 1

Pisces only. 
In pisces the oxygenated blood is directly sent to all parts of the body. Then the deoxygenated blood is sent to the heart and the heart pumps the blood to the gills for oxygenation

Answer 2

hi mate,

==> Pisces are the 'group of animals' whose 'heart' does not pump 'oxygenated blood' to different 'parts of the body'

==> In Pisces (fishes), the heart is 2 chambered oral pumps deoxygenated blood to me gills, where oxygenation takes place by diffusion.

==> The oxygenated blood from the gills is supplied to the body parts where oxygen is utilized and CO2 enters H making the blood deoxygenated.

==> This deoxygenated blood returns to the heart. Thus, it has single circulation, i.e., blood passes through the heart only once during one complete cycle.

i hope it helps you.